TURBINE AUXILIARIES
CHARGING, CHANGEOVER
&
ISOLATION PROCEDURE
-1-
INDEX
S.NO
DESCRIPTION
PAGE
1.
CEP start up, Changeover, Isolation & Normalization procedure
4-9
2.
LPHs Charging & Isolation procedure
3.
Symptoms of LP heater Tube leakage & confirmation procedure
4.
GSC Charging and Isolation procedure
14-15
5.
BFP start up, Changeover, Isolation & Normalization procedure
16-22
6.
HPHs Charging & Isolation procedure (Stage-I, II & III)
23-28
7.
Symptoms of HP heater Tube leakage & confirmation procedure
8.
DMCW system Charging & isolation procedure
30-33
9.
DMCW/ECW pump start up, Changeover, Isolation &
Normalization procedure (Stage-II & III)
34-35
10-12
13
29
10. CLCW system Charging & isolation procedure
36-37
11. CLCW start up, Changeover, Isolation & Normalization
procedure (Stage-II& III)
38-39
12. Seal oil system (Initial charging, pump/fan start up, Changeover,
Isolation & normalization procedure)
40-47
13. MOT Cooler Initial Charging, Changeover & Isolation Procedure
48-50
14. Main Ejectors Changeover & Isolation procedure
51
15. Condenser vacuum pump start up, Changeover, Isolation &
normalization procedure
52-53
16. Condensate path Charging & Isolation procedure (Stage-I)
54-56
17. Feed water path Charging & Isolation procedure (Stage-I)
57-59
18. CW pass Charging & Isolation procedure (Stage-I)
60-61
19. Condenser Vacuum Pulling/ Killing procedure
62-64
-2-
20. ACW system charging, ACW pump Changeover & Isolation
procedure
65-67
21. H2 Cooler/ ACW booster pump start up, changeover & Isolation
procedure
68-70
22. H2 Coolers/ Exciter coolers Charging & Isolation procedure
71-72
23. H2 drier changeover & Isolation procedure
24. Generator Stator Water System; Pump and Cooler changeover &
Isolation procedure
25. Debris Filter operating procedure
-3-
73
74-76
77
CONDENSATE EXTRACTION PUMP
PRE-START CHECKS OF CEP:
1. Check from local that CEPs suction valve are open and open limit is coming in
UCB.
2. Ensure that hot well level is Adequate (different value for all stages) from UCB
transmitter value and switch and also from local gauge glass.
3. Check that all the bearing /winding temperatures of CEP is not high from UCB
temperature indications and from local temperature gauges.
4. Ensure that CEP re-circulation valve is Open.
5. Ensure that CEP Discharge valves are closed from local and their closed limit is
coming in UCB. Check its operation.
6. Check from local that Condensate pump gland sealing water-isolating valve is
Open (sources: CST/CEP discharge).
7. Check from local that Condensate pump vacuum balancing valve is OPEN.
8. Check from local that Condensate pump thrust bearing cooling water line
isolating valve is OPEN
9. Check from local that Condensate pump bearing oil level is normal from level
gauge
10. Ensure electrical Supply (Breaker in service/Remote) is available from BC-bay
11. Check from local that Condensate pump EPB is release.
12. The entire LPHs (1/2/3) inlet and outlet valve are CLOSED and their bypass
valves are OPEN. Ensure from Local that the entire inlet/outlet/bypass valve
sealing water line is charged.
13. Ensure form local as well as from UCB that Deaerator inlet valve is OPEN.
14. Ensure from Local that CEP vent valve before NRV and
Line vents are OPEN.
-4-
15. Crack open suction valve of selected CEP. Fill and vent the pump up to highest
level vent. Close the vent valves in crack opened condition.
16. Normalize air supply to re-circulation control valve and
Ensure that it is opened fully.
17. Check that HW level controller, D/A level and cycle make up controller are
closed.
18. Intimate Local operator prior to starting of pump.
STARTING PROCEDURE OF CEP
WHEN BOTH THE PUMPS ARE OFF
1. Check that all pre checks are over from UCB/LOCAL before starting any CEP.
2. START CEP motor. CEP starting current comes down to 20A after 5 sec.
verify from UCB ammeter. Close all the vent which have been left crack open.
3. CEP discharge pressure increases to 25 Kg/cm2 approx. Check from UCB that
CEPs discharge valve is open. Its OPEN limit should come in UCB.
4. Now from local CLOSE the air vents on Condensate lines and
also monitor the suction strainer DP.
5. Load the Condensate pump by Opening D/A level control valve
CEP current will increase and discharge pressure decrease
proportionally. Condensate flow to D/A starts increasing.
Check it in UCB.
6. INSTRUCT the local operator to check the Bearing temperature
and Vibration of Pump. Also regularly monitor the bearing temp., Winding
temp.and vibration of pump in UCB.
-5-
7. CHECK that the second condensate pump is ready for starting
and is available on STANDBY. Breaker control switch is on
service/remote position.
8. Standby Pump is OK. All permissive are SATISFIED. UCB
check. All local line-ups are COMPLETE.
WHEN ONE PUMP IS RUNNING
1. Before starting the second Condensate pump check that all the
Pre-start checks are satisfied from Local /UCB
2. Start the CEP motor. CEP discharge header pressure improves a little
(At a discharge pressure <17 Kg/cm2, the standby CEP can take start
automatically).The motor current of other CEP drops slightly.
3. Check bearing/winding temperature and vibration of running CEP from
Local/UCB.
CEP SHUTDOWN PROCEDURE
WHEN ONE PUMP IS RUNNING
1. Intimate the local operator about pre-check of standby CEP
(Lubrication oil level, bearing /winding temperature, Manual
Suction valve open from Local).
2. After pre-check switch off the SLC of CEPs and check Release for second CEP
is available. If it is available, start the second CEP. Observe the condensate flows
will be improved slightly. The current of first CEP will slightly come down. If the
D/A level controller and re-circulation valve Comes in manual mode put it in auto
mode again
-6-
3. Now after assured from local site as well UCB that the second
CEP is running smoothly change the priority selection from first
one CEP to second CEP (which is now to be taken is service)
and stop the first CEP.
4. Observe the hot well level, and If the D/A level controller and re-circulation valve
comes in manual mode put it in auto mode again. Also check the Hot well
DO/Deaerator O2 while changing the CEP .If it increases and does not come
down after a short span of time, check the sealing of CEP and inform to TMD.
5. Close the Suction and Discharge valves .If any maintenance is to
be carried out. And also isolate it from Electrical side Also assure
from local as well as UCB
CEP ISOLATION PROCEDURE
1. SLC of CEPs should be OFF.
2. Ensure electrical isolation of CEP breaker.
3. Close CEP suction valve and its close limit in UCB.
4. Close CEP discharge valve and ensure its electrical isolation.
5. Close CEP vent to condenser line valve.
6. Open suction strainer vents and drains if required by maint. Group.
7. Close gland sealing/cooling line isolating valve if required by maint. Group.
8. Close thrust brg cooling water line valve if required by maint. Group.
-7-
CEP NORMALISATION PROCEDURE
1. Open gland sealing/cooling line isolating valve.
2. Open thrust brg cooling water line valve.
3. Check oil level in thrust bearing. It should be at normal level.
4. Close suction strainer vents and drains.
5. Open CEP vent to condenser line valve before opening CEP suction valve to
avoid disturbance in running CEP suction flow.
6. Gradually open CEP suction valve and observe condensate water flow/
pressure and condensate DO. Check open limit of valve in UCB.
7. Normalise electrical supply of CEP discharge valve and check its operation.
8. Ensure normalisation of CEP breaker.
9. Ensure trial operation of CEP as per procedure mentioned above and keep
SLC ON, subsequent to stoppage of pump.
-8-
REGULAR CHECKS FOR STANDBY CEP:
• Ensure normalization of CEP as per CEP normalization procedure.
• Check that all start permissives are available and AUTO selection of pump.
• Check that CEP discharge valve & vent valve are open.
• Check that thrust bearing oil level is adequate, and Bearing/gland
cooling/sealing water lines are charged.
• All C&I instruments are healthy.
CHECKS AFTER AUTO START OF STANDBY CEP:
• AUTO opening of DM cooling water line valve (for motor & working oil
coolers).
• AUTO closing of pump vent valve
• No leakage/abnormality at site.
• Keep close watch on following parameters;
All bearing (motor, thrust brg) temp, Motor winding temp, Pump
discharge/header pressure, Condensate water flow, Hot well level, pump
current etc.
• Reason for AUTO start.
-9-
LP HEATERS
A.
LP HEATERS CHARGING
1. Before charging the LP Heaters, check for the following:
a. All maintenance work on valves and equipment of regenerative system
should be completed
b. All pressure, temperature and level gauges should be taken into service
c. Extraction lines drain line valves should be in open condition
d. LP heaters shell vents to condenser should be in open condition
e. LP heaters tube vent valves should be in open condition
f. Drip level control valves should be in open condition and on remote
g. Main condensate line drains should be closed
h. Condensate system should be running up to Deaerator through LP
Heaters bypass valves and CEP re-circulation valve on AUTO.
i. Sufficient make up water should be available.
(Ensure running of DM make up pumps and adequate CST level with
HOT WELL level control valves in normalize condition)
2. Charging from the water side
a. Crack open LP heater charging valves until a steady flow of water is
observed from the vent
b. Observe the gauge glass level indicator/level transmitters for no increase
in level and the shell pressure (in case of heater tube leakage there will
be an increase in level and shell press)
c. Close the air vent
- 10 -
d. Open the inlet and outlet valves fully. During opening of inlet and outlet
valves keep continuous watch on CONDENSATE WATER FLOW.
3. Charging from the steam side ( to be done after the unit load has
reached beyond 40 MW)
a. Crack open the extraction valve of LP Heater for warming. Note for the
rise in the condensate temperature.
b. Gradually open the extraction valve fully. Extraction drain valve start to
close.
c. Start gradual closing of alternate drip to condenser and the LPH level
low alarm on the annunciation facia disappears.
d. Modulate LP heater normal drip valve to maintain LP heater level.
e. Check for the rise in condensate temperature.
f. Put the normal and alternate drip valves control on AUTO mode and
observe their response and LPHs drip level for some time.
Note: All the LP heaters should be charged sequentially with LPH-1 first
and moving on LPH-2, LPH-3 and so on.
- 11 -
B. ISOLATION OF LP HEATERS
1. Isolation from the steam side:
a. Gradually close the extraction valve fully.
b. While closing extraction valve, observe drip level of heater. If required,
take the drip level control in manual mode and open normal/alternate
drip valve to full.
c. Close extraction line FC NRV if provided and isolate electrical supply of
FC NRV solenoid.
d. Observe heater inlet and outlet condensate water temperature. There
should be no gain in condensate temperature across heater. Ensure
electrical isolation of extraction valve.
e. Close heater shell vent to condenser.
f. Open shell vent and drain to atmosphere and keep close watch on
condenser vacuum.
g. Open extraction line drain valve to flash tank. Ensure its electrical
isolation.
2. Isolation from the water side
a. Open LP heater bypass valve gradually. Ensure from local.
b. Close heater inlet and outlet valve gradually. Keep close watch on
condensate water press/ flow during above operations. Ensure electrical
isolation of valves.
c. Open waterside vents and drains. While opening water side vents and
drains, keep close watch on condenser vacuum.
Note: On isolation of heaters, first ensure extraction side isolation then
isolation from waterside.
- 12 -
SYMPTOMS OF LP HEATER TUBE LEAKAGE:
Increase in opening of normal drip control valve. UCB & local check.
Intermittent opening of alternate drip control valve. UCB & local check.
Difference in condensate water flow before and after LP heaters.
Increase in CEP current.
Ensure confirmation of tube leakage as per following procedure:
1. Isolate LP heater from extraction side.
2. Bypass LP heater from condensate side.
3. Reduce drip level to minimum by operating drip valves.
4. Gradually charge LP heater from condensate side.
5. Observe drip level and shell pressure. In case of tube leakage, increase
in drip level and shell pressure will be observed.
6. Close LP heater shell vent to condenser
7. Open LP heater shell drains to atmosphere. In case of tube leakage,
water will start coming out from drains.
Note: In case of tube leakage, isolate LP heater as per procedure mentioned
above.
- 13 -
GLAND STEAM CONDENSER
A.
GLAND STEAM CONDENSER CHARGING
1. Before charging the GSC, check for the following:
a. All maintenance work on valves and Gland Steam Condenser should be
completed
b. All pressure, temperature and level gauges should be taken into service
c. Condensate system should be running up to Deaerator through GSC
bypass valves and CEP re-circulation valve on AUTO.
d. Ensure that steam line syphon is filled with water.
e. Ensure availability of GSC VEFs and all valves pertaining to Gland
Steam Condenser system.
2. Start opening GSC inlet and outlet line valve on condensate path. Gradually
open to full.
3. Close GSC bypass line valve. Observe condensate flow and pressure in UCB.
4. Ensure running of one GSC VEF with its suction valve open.
5. Close GSC drip to atmosphere line manual valve
6. Open GSC drip to condenser line manual isolating valve. Observe condenser
vacuum.
7. Close GSC drip to atmosphere line manual valve.
8. Start opening steam line valve at GSC. Gradually open to full.
9. Gradually close vent to atmosphere line valve and keep close watch on seal
steam hdr press and condenser vacuum.
- 14 -
B.
GLAND STEAM CONDENSER ISOLATION
a. Start opening GSC vent to atmosphere line valve. Gradually open to full.
b. Gradually close GSC steam line, to GSC, valve and observe seal steam
header pressure and condenser vacuum.
c. After closing steam line valve, Close GSC drip to condenser line manual
valves. If required, open drip to atmosphere line valve.
d. Start opening GSC bypass line valve (condensate side). Gradually open
to full. Keep close watch on BFPs suction filter DP and suction flow,
Feed water flow and Boiler water Sio2.
e. Start closing GSC inlet and outlet line valve on condensate path.
Gradually close to full. Observe condensate water flow/pressure.
- 15 -
BOILER FEED PUMP
PRE-START CHECKS OF BFP
1. Ensure that Deaerator level is adequate (for stage-I - 840mm, for stage-II
>400mm, for stage-III >400mm) Check this level from UCB transmitter value and
also Check from local gauge glass of Deaerator.
2. Check that ECW system is available.
3. CEP running and condensate system available up to Deaerator.
4. Instrument air available for recirculation valve and seal water module.
5. Interlocks and protections of BFP have been checked.
6. Close the drains of the ECW inlet and outlet headers of the BFPs.
7. Line up the following coolers
- Both motor cooler (This should be charged first to vent out all air in the ECW
system)
- Both working oil cooler
- Both lubrication oil cooler
8. Check from local that BFP suction manual value is OPEN and the OPEN limit is
coming in UCB .
9. Check BFP booster pump suction pressure is ADEQUATE. (In stage –III BFP
booster pump suction pr.>5 ksc).From local suction pressure gauge and also check
this value in UCB.
10. Check from Local that BFP manual re-circulation valve at Deaerator floor is
Open 100%.
- 16 -
11. Check from Local that BFP cooling water pressure is adequate (for stage-III CW
valve close permissive is given)
12. Check from local as well as all the Bearing (Booster pump,hydraulic coupling,
Main pump) temp are normal and all RTD are mounted.
13. Check from Local and UCB that all the winding temp are showing normal value.
14. Check from Local and in UCB BFP lubrication oil pressure is ADEQUATE
(in stage –I >2.5 ksc, stage-II >2.0 Ksc, stage -III>2.0 ksc).AOP is in running
condition for available BFP and lubrication Oil filter DP<.2 Ksc
15. Check in UCB and from Local that BFP scoop tube is on minimum position
16. Check from local that hydraulic oil tank level is adequate
(Permissive is given in Stage-III)
17. Also check from Local that Working oil coolers, lubrication oil cooler are in
charged position. All the manual valve for cooling water to bearing are OPEN.
18. Check from Local that BFP motor air box cooling water Inlet/outlet manual
valves are OPEN.
19. Check from Local BFP suction strainer DP not high<.2 Ksc.
20. Check from local that Emergency Push Button of BFP is released and it contact
are coming in DMS .
21. Ensure from BC-BAY electrical supply of BFP is normal.
22. For first BFP check from local that all the air vents on suction & discharge line of
BFP and feed regulating station are closed.
23. For first BFP started Check from UCB that spray pressure control valves on
HP bypass & AUX.PRDS station are CLOSED.
24. Check from Local suction strainer drain valve is in CLOSED position.
25. For first BFP started Check HPHs are in BYPASS condition. Group bypass
valves are in ‘Bypass’ mode or individual HPHs Bypass valves are OPEN.
26. From UCB CLOSED Feed Regulating Station control valve.
27. Check that Economiser inlet valve E-2 is in open condition.
28. check from UCB and Local Header block valves on Super heater
attemperation lines and Reheater are closed.
- 17 -
29. BFP local operator intimated before starting of BFP.
30. Check that the following drains valve are closed
- Drain valve of suction strainer
-Two drain valve of booster pump
- Drain valve of main pump strainer
- Drain valve of main pump
31. Open the Motorised vent valve of transfer line and main pump strainer.
Close the vent valve when water starts flowing.
32. Open the cooling water supply and return valve for booster pump seal and gland
cooling.
33. Take both the mechanical seal filter into service.
BFP STARTING PROCEDURE
WHEN ALL PUMPS ARE OFF
1. Check from local and from UCB that the above PRE-CHECKS are COMPLETED
and all BFP permissives are available.
2. Start the Boiler Feed Pump motor. Breaker will closed and motor takes starting
current to no load current of 125 Amp approx. BFP header discharge Pressure
increases up to 85 kg/cm2.
3. Check from local and UCB that Integral bypass valve of the BFP main discharge
valve start opening. After Integral bypass valve are fully open. BFP main discharge
valve starts opening and its indication come in UCB. Suction flow increases to 150
Kg/cm2 approx.
4. Motorised cooling water valve starts opening for supplies cooling water to motor
air box and working oil cooler on interlock.
5. BFP aux. oil pump goes off as the main oil pump takes over, on interlock.
- 18 -
6. Take out of scoop control to manual mode, as it will come in auto mode after a
delay of 5 sec. on interlock.
7. Raise BFP scoop tube position to get desired feed water.
BFP discharge pressure rises.
8. Feed water flow through the BFP starts increases above150T/Hr.
BFP header pr. Low alarm gets reset in UCB.
9. Re-circulation valve auto release become available if BFP flow exceeds 210 T/h.
10. Open feed regulating station low range controllers isolating valves. Integral
bypass valves of FW open up and indication comes in UCB.
11. Instruct local operator to check bearing vibration and temp locally.
12. Check from local pump balance leak off pressure. Check that water is flowing in
the balance line by observing ‘Balance pressure’ about 0.5Kg/cm2 higher than the
booster pump discharge pressure. If the Pr. /Flow in the balance line are exceed
normal value then check thrust brg. temperature.
WHEN ONE PUMP IS RUNNING
1. Check before starting the second pump that all pre-start checks are over from
local and UCB.
2. Check that all permissive for starting of BFP is available.
3. Auxiliary oil pump is ON and lubrication oil pressure is ADEQUATE.
Also check that oil level in Hydraulic coupling tank is normal
4. BFP scoop tube is minimum. And BFP selector switch is normal
5. Start the BFP motor. BFP breaker closed. Motor will take no load current.
Scoop tube controller will come in auto mode, transfer it in to manual mode.
6. After BFP start Motorised cooling water valve open up, and BFP auxiliary oil
pump trip and WOP take over on interlock.
- 19 -
7. Now increase the scoop tube position for increase the discharge pressure.
Increase the scoop position by keeping close watch on Drum level, FRS DP,
suction/discharge DT. ,Bearing vibration/temperatures etc..
8. Adjust the scoop of the two running BFPs to equalize load. BFPS discharge
pressure/ flow indications must become approx. equal.
9. Adjust BFPs Scoop master controller equal to BFPs scoop tube become
position. Controller error on the scoop controls of the running BFPs should be zero.
10. Transfer running BFP scoop control to auto. Maintain DP across FRS
5-7Kg/cm2.Transfer BFP master control to auto when actual & set value of DP
is matching.BFP master trips to Manual if any BFPs trips or individual BFP control is
changed to Manual mode
BFP SHUTDOWN PROCEDURE
1. The BFP, which is to be shutdown, keep out that BFP from standby Mode.
Transfer scoop control of that BFP to manual.
2. Reduce scoop tube controller of BFP. BFP discharge pressure and flow starts
decreasing. Keep close watch on FRS DP and Drum Level.
3. After the discharge comes to 100-90 T/H recirculation valve will open
100%.Reduce the scoop tube to minimum position. Then stop the BFP motor.
Motorised cooling water valve starts closing. AOP will take start on AUTO..
BFP ISOLATION PROCEDURE
1. Perform electrical isolation of BFP.
2. Close BFP suction and discharge valve.
3. Perform electrical isolation of BFP discharge valve.
- 20 -
Incase of St-2&3, electrical isolation of main pump discharge line vent valves
after opening it.
4. Ensure closing of Motorised isolating valve on cooling water line to
motor/working oil coolers and ensure its electrical isolation if required by
maintenance group.
5. Close BFP manual re-circulation valve at DEA. floor.
6. Open pump suction strainer vent and drain valves.
7. Open Booster/ main pump casing drain valves.
8. Open Booster pump suction/discharge line vent/drain valves.
9. Stop and isolate AOP if required by maintenance group.
BFP NORMALISATION PROCEDURE
1. Crack open BFP suction valve and Close all drain and vent valves of suction
strainer, booster and main pump after ensuring proper flow of water.
2. Open BFP manual re-circulation valve at DEA. floor.
3. Ensure normal running of AOP. Observe Lub oil pressure both at local and in
UCB.
4. Ensure charging of Lub oil and working oil coolers from oil and waterside.
5. Ensure healthiness of all temp/pressure measurement points in UCB and at
local.
6. Perform electrical normalisation of BFP discharge valve.
Incase of St-2&3, normalise electrical supply of main pump discharge line vent
valves and check its operation.
7. Ensure operation of its discharge and re-circulation valve from UCB/local.
8. Check healthiness of its scoop tube from UCB.
9. Perform normalisation of BFP breaker.
- 21 -
REGULAR CHECKS FOR STANDBY BFP:
• Ensure normalization of BFP as per BFP normalization procedure.
• Check that all start permissives are available and AUTO selection of pump.
• Check that BFP discharge valve is open and scoop is varying according to
scoop master demand.
• Check that lub oil pressure & lub oil filter DP are normal at local and no alarm
is appearing in UCB.
• Check that hydraulic oil tank level is normal and oil quality is good (no
abnormality such as moisture, foaming etc)
• Oil coolers are charged from oil and water side.
• Seal water coolers are charged from cooling water side.
• Seal water lines of main pump (both DE & NDE) are charged through
magnetic filter and bypass valve is closed.
• All C&I instruments are healthy.
CHECKS AFTER AUTO START OF STANDBY BFP:
• AUTO opening of DM cooling water line valve (for motor & working oil
coolers).
• AUTO closing of re-circulation valve.
• AUTO cut off of AOP.
• No leakage/abnormality at site.
• Keep close watch on following parameters;
All bearing temp., Lub oil pressure, Lub oil & working oil temp (both at local &
UCB), BFP suction flow, Feed water flow after HPHs, pump diff temp, Drum level,
FRS DP, pump current etc
- 22 -
HP HEATERS (STAGE-I)
A. HPHs CHARGING PROCEDURE
1. CHARGING OF HPHs FROM WATER SIDE:
a. Check the following, before charging of HPHs from water side:
- No PTW is pending on HPHs and its group bypass valves.
- Group bypass valves are gagged.
- All drain valves and vent valves should remain open as per requirement.
- HPHs dump valve (DW 400) is closed.
- Group bypass protection valves (DW-109 & 399) are available and closed.
Ensure open condition of manual isolating valves of DW-109 & 399.
b. Open charging line valve gradually.
c. Ensure that water is coming out from all drains.
d. After some time close HPHs inlet line drains.
Note: Inform shift chemist to report silica level in HPHs.
e. After achieving silica level and adequate temperature, close all drains and
vent valve.
f. Gradually remove gagging of HPHs group bypass valves simultaneously.
Keep FW-56 valve opening slightly more than FW-55 to avoid feed water
flow interruption.
Note: While removing gagging of Group bypass valves one should remain in
continuous touch with UCB.
- 23 -
2. CHARGING OF HPHs FROM STEAM SIDE:
a. Check the following, before charging from steam side:
- Shell drain valves should be closed.
- Healthiness of all drip line control valves.(Before checking operation of valves
ensure closing of their manual isolating valves)
- Open manual isolating valves before and after all drip line control valves.
- Shell vent to atmosphere should be closed.
- Shell vent to condenser should be open.(Ensure closing of shell drains prior to
it)
b. Open drip to condenser valve (HD-20/23) as per requirement.
c. Gradually open extraction line integral bypass valve followed by main valve.
(Check locally for any abnormality/ line hammering)
d. Regulate drip line control valves and maintain drip level.
e. Put drip line control valves on auto and observe level for some time.
C. HPHs ISOLATION PROCEDURE
a. Gradually close extraction valve of HPH to be isolated. Keep close watch on
unit parameters such as load, MS temp/press, FW temp after heaters etc. and
drip level. If required, take drip to condenser line control valve in manual and
open it as per requirement.
b. Ensure complete closing of extraction line valve from local. If required
tightened it.
c. Close extraction line FC NRV (if provided) and isolate solenoid valve supply.
d. Perform electrical isolation of extraction line valve.
e. Close shell vent to condenser.
- 24 -
f. Open shell vent/drain line, to atmosphere, valves and keep close watch on
condenser vacuum for some time.
g. Isolate both HPHs from feed water side by opening group bypass protection
valves (DW-109 & 399) from UCB.
h. Ensure complete closing of Group bypass valves (FW-55 & 56) at local and
gagging of both valves.
i. Open feed water line drain line valves before and after HPHs to depressurize
it. Keep close watch on condenser vacuum for some time.
j. Close manual isolating valves of all drip valves tightly.
k. Electrical isolation of all isolating valves (before, after and bypass) of HPHs on
feed water line.
- 25 -
HP HEATERS (STAGE-II& III)
A. HP HEATERS CHARGING
1. Before charging the HP Heaters, check for the following:
a. All maintenance work on valves and equipment of feed water system
should be completed
b. All pressure, temperature and level gauges/switches should be taken
into service.
c. HP heaters tube vent valves should be in open condition
d. HP heaters tube side drain valves should be in close condition
e. Extraction lines drain line valves should be in open condition
f. HP heater shell vents to condenser should be open
g. HP heater shell drains to atmosphere should be closed
h. Drip level control valves should be in open condition and operating
properly on interlock from remote
i. Feed water system is running normally through bypass valves of HP
heaters and on re-circulation
j. Main feed water line drains should be closed
2. Charging from water side
a. Crack open the HP heater charging valve up to an extent that heater will
charge slowly and smoothly and the air will be slowly released from the
vents
b. Observe the gauge glass level indicator/level transmitters for no increase
in level and the shell pressure (in case of heater tube leakage there will
be an increase in level and shell pressure)
- 26 -
c. When the air is completely vented out and a steady flow of water starts
coming out of the vents, close the air vents
d. Open the inlet and outlet valves fully. During opening of inlet and outlet
valves keep continuous watch on FEED WATER PRESS/FLOW.
3. Charging from steam side ( to be done after the unit load has reached
beyond 120 MW)
a. Crack open the extraction steam valve and start warming up the HP
heaters and keep a close watch on drip level, shell pressure, and for any
other abnormalities such as hammering etc.
b. Extraction line drain valves will start to close.
c. Regulate HP heater alternate drip valve to condenser to maintain heater
level and “HP heater low level” alarm on the annunciation facia clears
off.
d. Modulate HP heater normal drip valve to maintain the heater level.
e. Feed water temperature after HP heater starts to increase.
Note: All the HP heaters to be charged sequentially with HPH-5 charged first
and moving to HPH-6 and so on. During charging of HPHs, keep close watch
on unit parameters such as MS press / temp, Feed water temp after heaters &
Boiler water silica level.
B. ISOLATION OF HP HEATERS
1. Isolation from the steam side:
a. Gradually close the extraction valve fully. Ensure electrical isolation of
extraction valve.
b. While closing extraction valve, observe drip level of heater. If required,
take the drip level control in manual mode and open normal/alternate
drip valve to full.
- 27 -
c. Open extraction line drain valve to flash tank. Ensure its electrical
isolation.
d. Close extraction line FC NRV if provided and isolate electrical supply of
FC NRV solenoid.
e. Observe heater inlet and outlet feed water temperature. There should be
no gain in feed water temperature across heater.
f. Close heater shell vent to condenser.
g. Open shell drain to atmosphere. While opening it keep watch on
condenser vacuum.
Note: During isolation of HPHs, keep close watch on unit parameters such as
MS press/temp, Feed water temp after heaters, FG temp. at APH inlet/outlet
etc.
4. Isolation from the water side
a. Open HP heater bypass valve gradually. Ensure from local.
b. Close heater inlet and outlet valve gradually. Keep close watch on feed
water press/ flow during above operations.Ensure electrical isolation of
valves.
c. Open waterside vents and drains. While opening water side vents and
drains, keep close watch on condenser vacuum.
Note: On isolation of heaters, first ensure extraction side isolation then
isolation from waterside.
- 28 -
SYMPTOMS OF HP HEATER TUBE LEAKAGE:
Increase in opening of normal drip control valve. UCB & local check.
Intermittent opening of alternate drip control valve. UCB & local check.
Difference in Feed water flow before and after HP heaters.
Increase in BFPs current and scoop position.
Ensure confirmation of tube leakage as per following procedure:
1. Isolate HP heater from extraction side. Observe drip level. In case of tube
leakage their will not be much drop in drip level.
2. Bypass HP heater from Feed water side.
3. Reduce drip level to minimum by operating drip valves.
4. Gradually charge HP heaters from Feed water side.
5. Observe drip level and shell pressure. In case of tube leakage, increase
in drip level and shell pressure will be observed.
6. Close HP heater shell vent to condenser
7. Open HP heater shell drains to atmosphere. In case of tube leakage,
water will start coming out from drains.
Note: In case of tube leakage confirmation, isolate HP heater as per
procedure mentioned above.
- 29 -
DMCW SYSTEM
A. DMCW SYSTEM CHARGING PROCEDURE:
1. Ensure all PTWs related to ECW tank and associated piping are returned.
2. No pending PTW on main DMCW pumps
3. Check DOR of all DMCW pump motors
4. If DOR is OK inform TMD for coupling of DMCW pumps
5. Physically check the location and ensure that any kind of work is not being
done
6. Men and material are removed from the site.
7. Check ECW tank internals and ensure that there is not any kind of foreign
material, cotton waste etc.
8. Close the man hole of ECW tank
9. Close the drain valve of ECW tank.
10. Ensure that the vent valve of tank is open.
11. Ensure that level transmitter/indicator valves are open.
12. Close the tank outlet valve at 6m in TG area.
13. Coordinate with other units for taking DM water
14. Manually open the tank make-up line valve (P010) around 10-15 % to facilitate
slow filling of line up to P010 so that air in the line get released properly.
15. Before charging the main system ensure that
- Clearance is available for main system charging
- No pending PTW on main DMCW system
- No pending PTW on main DMCW pumps
- 30 -
- Boiler side valve is closed
- Turbine side valve is closed
- DM water to and from compressor house valves are closed
16. Open DMCW suction header vent
17. Open recirculation valve
18. Open DMCW pumps suction valve
19. Open DMCW pumps vent
20. Open PHE inlet and outlet vent
21. Open PHE outlet header vent
22. Close all the drains in the system
23. Now partially open the make-up line valve at 6m in TG area. The slow filling
rate will ensure proper air release from the system.
24. Keep all the vents open as long as air or air water mixture comes out of it.
25. Normalize supply of DMCW pump discharge valves
26. Normalize power supply of at least one DMCW pump.
27. Check the following, before starting pump
- Pumps rotates freely by hand
- Suction valve fully open
- The pump and suction pipe is fully primed
- Valve on delivery side is closed
- Stuffing box packing is properly tightened
- Pump power supply is normalised
- 31 -
28. When only water starts coming out of vent and pressure indicator in suction
header shows pressure, slowly open the make-up valve fully and line up one
DMCW pump.
29. Ensure that PHEs inlet and outlet line vent valves are full open.
30. Crack open DMCW pump discharge valve from local and slowly charge
DMCW lines to PHEs.
31. Gradually open pump discharge valve to full.
32. Close PHE inlet and outlet line vent valves when clear water starts coming out.
33. Start one DMCW pump. Before starting pump, ensure healthiness of
discharge valve from UCB/local.
34. After starting the pump ensures that discharge valve is fully opened within 90
seconds.
35. After running the pump check that pump is running smooth, leakage through
stuffing box is normal (60 – 80 drops per minute), discharge pressure is as
specified and power consumption is within the limit.
Now the DMCW system is charged and ready to charge different equipments.
Note: Before charging any area or equipment care has to be taken that all the vents
are open to evacuate air. Re-circulation valve has to be regulated as the water flows
to different areas.
- 32 -
B. DMCW SYSTEM ISOLATION PROCEDURE
1. To isolate and drain the DMCW system
2.
Ensure clearance is available for system isolation.
3.
Ensure IAC PAC compressors cooling water is available.
4.
Ensure DM cooling water to/from compressor house valves are closed.
5.
Shut down all the DMCW pumps.
6. Ensure that discharge valve of pump is closed and pump is not rotating
in reverse direction.
7.
Isolate the supply of DMCW pumps.
8.
Close and isolate the supply of P010.
9.
Isolate the boiler and turbine area by closing respective valves.
10. Close sump pump lubrication/cooling water line valve
11. Open recirculation valve.
12. Open DMCW system drain
13. Open suction header and discharge header vents.
14. Wait until the water from drain stops.
Now the system is drained and ready for maintenance work.
- 33 -
DMCW PUMP
A. DMCW PUMP START-UP PROCEDURE
1. Check all the PTWs on pump or motor are cancelled
2. Locally check that man and material are removed from site
3. Check pump and motor coupling and readiness of pump for operation
4. Close pump drain valve, if open
5. Crack open the pump suction valve and fully open pump vent valve
6. When water starts coming out of pump vent, fully open the suction valve
7. Close pump vent valve
8. Now normalise the power supply of pump and its discharge valve
9. Ensure that discharge valve is close
10. Keep the location operator at site and start the pump
11. Discharge valve should open within 90 seconds
12. Check discharge pressure and motor current
13. Ask location operator for any abnormal sound, vibration and any leakage
14. If everything is normal shutdown other pump if it has to be taken in service
Note: In case suction header pressure is having hunting and going high,
Immediately Crack open suction header vent valve/ any vent valve at higher
elevation i.e H2 cooler or Exciter cooler vent, to evacuate entrapped air from the
DMCW system.
- 34 -
B. DMCW PUMP CHANGEOVER PROCEDURE
1. Put the standby pump out of standby mode
2. Close discharge valve and ensure that suction valve is fully open
3. Keep the location operator at site and start the pump
4. Discharge valve should open within 90 seconds
5. Check discharge pressure and motor current
6. Ask location operator for any abnormal sound, vibration and any leakage
7. If everything is normal shutdown other pump
8. Put the other pump in standby mode if no permit has to be issued on it
C. DMCW PUMP ISOLATION PROCEDURE
1. Changeover the pump if required as per above procedure
2. Close the discharge valve of pump
3. Isolate the power supply of pump and discharge valve
4. Put danger tag on the modules
5. Close suction valve of pump
6. Open pump drain valve and vent valve
7. Tighten suction or discharge valve if there is any passing
8. When water stops coming out from drain valve, PTW on pump can be issued.
- 35 -
CLCW SYSTEM
A. CLCW SYSTEM CHARGING PROCEDURE
1. Ensure all PTWs related to CLCW system are returned
2. No pending PTW on main CLCW pumps
3. Check DOR of all CLCW pump motors
4. If DOR is OK inform TMD for coupling of CLCW pumps
5. Physically check the location and ensure that any kind of work is not being
done and men and material are removed from the site
6.
Ensure that all the piping joints are tightened
7. Ensure that condenser cooling water system is charged
8. Ensure that all the drains in the system are closed
9. Normalize supply of CLCW pump discharge valves
10. Open CLCW pump suction and discharge valve
11.Ensure that system is lined-up for filling. All PHEs should be lined up from
CLCW side.
12.Ensure that all the vents (strainer, after PHE) in the system are open
13.Crack open the CW inlet line valve and allow slow filling of the system to
facilitate proper air venting.
14. Keep all the vents open as long as air or air water mixture comes out of it
15. Slowly fully open the CW inlet line valve and CW outlet line valve
16.Close all the vents when water starts coming out of them
17.Check choking condition of basket filters. Get it cleaned if required.
Put one filter in service
18.Normalize power supply of CLCW pumps and
- 36 -
Check the following before starting any pump
- Pumps rotates freely by hand
- Suction valve is fully open
- The pump and suction pipe is fully primed
- Valve on delivery side is closed
- Stuffing box packing is properly tightened
- Pump power supply is normalized
- System is lined-up
Now the CLCW system is charged and ready for operation.
B. CLCW SYSTEM ISOLATION PROCEDURE
1. Ensure clearance for system isolation
2. Ensure cooling requirement of DMCW System
3. Shut down all the CLCW pumps
4. Ensure that discharge valve/NRV of pump is closed and pump is not rotating
in reverse direction
5. Isolate the power supply of all the CLCW pumps
6. Close the CW inlet side valve
7. Close the outlet vale to CW outlet line
8. Close sump pump lubrication/cooling water line valve
9. Open basket filter drains
10. Open filter and line vents
Note: Wait until the water from drain stops.
Now the system is drained and ready for maintenance work.
- 37 -
CLCW PUMP
A. CLCW PUMP START-UP PROCEDURE
1. Check all the PTWs on pump or motor are cancelled
2. Locally check that man and material are removed from site
3. Check pump and motor coupling and readiness of pump for operation
4. Close pump drain valve, if open
5. Crack open the pump suction valve and fully open pump vent valve
6. When water starts coming out of pump vent, fully open the suction valve
7. Close pump vent valve
8. Now normalise the power supply of pump and its discharge valve
9. Ensure that discharge valve is close
10. Keep the location operator at site and start the pump
11. Discharge valve should open within 90 seconds
12. Check discharge pressure and motor current
13. Ask location operator for any abnormal sound, vibration and any leakage
14. If everything is normal shutdown other pump if it has to be taken in service
- 38 -
B. CLCW PUMP CHANGEOVER PROCEDURE
1. Put the standby pump out of standby mode
2. Close discharge valve and ensure that suction valve is fully open
3. Keep the location operator at site and start the pump
4. Discharge valve should open within 90 seconds
5. Check discharge pressure and motor current
6. Ask location operator for any abnormal sound, vibration and any leakage
7. If everything is normal shutdown other pump
8. Put the other pump in standby mode if no permit has to be issued on it
C. CLCW PUMP ISOLATION PROCEDURE
1. Changeover the pump if required as per above procedure
2. Close the discharge valve of pump
3. Isolate the power supply of pump and discharge valve
4. Put danger tag on the modules
5. Close suction valve of pump
6. Open pump drain valve and vent valve
7. Tighten suction or discharge valve if there is any passing
8. When water stops coming out from drain valve, PTW on pump can be issued.
- 39 -
GENERATOR SEAL OIL SYSTEM
1. PRE-REQUISITES AND STATE OF PLANT:
- No PTW is pending & Seal oil circuit is ready for charging.
- MOT is filled, AOP is in service and bearings are charged.
- Governing oil shutoff valve, in MOT room, is open.
- Seal oil storage tank is filled with oil.
- All pressure gauges, switches and transmitters in seal oil system must have
been mounted properly. Shutoff valves before all PGs, PSs and PTs must be
open.
- All level indicators in seal oil system must be calibrated and activated.
2. FILLING AND INITIAL OPERATION OF SEAL OIL CIRCUIT:
Open all pressure gauges isolating valves.
Ensure open condition of following valves in signal pipes:
- Seal oil signal to DPRV-A1 & A2.
- H2 gas signal oil to DPRV-A1 & A2
Ensure governing oil line PRV signal oil line isolating valve.
Open up stream isolating valve of PRV, in oil canal at TG floor, and ensure
flow of oil by touching pipe line.
Open PRV (Governing oil line) downstream isolating valve at seal oil unit
gradually and perform filling and venting operation of seal oil coolers and
filters.
Note: Before opening downstream isolating valve, ensure closing of oil
transfer valve at seal oil unit.
Fill seal oil coolers in the following manner:
- Open oil vents of the coolers.
- 40 -
- Fill both seal oil coolers with oil by bringing rotary transfer valve assembly in
centre. (Filling of seal oil coolers can be done one by one)
- Close oil vents of the coolers when bubble free oil emerges out from both the
coolers.
- When both the coolers are filled, take any one cooler in service by turning
rotary transfer valve assembly & other as standby.
Note: Observe MOT level, if required top up MOT.
Fill seal oil filters in the following manner:
- Open vent valve of both seal oil filters.
- Fill both seal oil filters with oil by bringing rotary transfer valve assembly in
centre. (Filling of seal oil coolers can be done one by one)
- Close oil vents of the filters when bubble free oil emerges out from both the
filters.
- When both the filters are filled, take any one filter in service by turning rotary
transfer valve assembly & other as standby.
- Charge DP gauges across both filters after proper venting.
Note: 1. Observe MOT level, if required top up MOT.
2. Now seal oil circuit is filled with oil up to DPRV-A1 & A2 isolating valves.
Observe seal oil pressure after seal oil filters at local pressure gauge.
Place one SOST exhauster is operation. Ensure that second exhauster is
ready for start up.
Gradually open DPRVs/ ring relief PRVs isolating valves and charge seal oil
circuit to generator seals (TE and EE).
Note: Ensure charging of seal oil circuit by touching individual lines
supply and drain lines)
Check for any oil leakage.
Observe seal oil parameters at following places:
- Seal oil pressure at local gauge after DPRV at seal oil unit.
- 41 -
(seal oil
- Seal oil flow to TE and EE seals.
- Ring relief oil flow to TE and EE seals.
- Seal oil pressure at TE and EE seals in UCB.
- Seal oil DP in UCB.
Observe rise in IOT level as H2 side drain, from seals, will be collected in IOT.
Fill seal oil vacuum tank with oil by opening shutoff valves at SOST
(MKW01AA151) and at seal oil vac. tank (MKW10AA101).
Note: 1. Observe MOT level if required top up MOT.
2. Now oil is available at the suction valve of seal oil pumps (2AC&1DC)
3. SEAL OIL PUMPS START-UP PROCEDURE:
Check that
- Motor is free to rotate.
- Coupling is OK and coupling guard is provided.
Gradually open suction valves of pumps and ensure proper venting of pumps
by opening vent screw with the help of TMD.
Open discharge valve of all seal oil pumps.
Ensure electrical normalisation of AC/DC seal oil pumps and put control of
pumps in manual mode.
Note: Keep DC seal oil pump local starter panel isolator switch in OFF
position to avoid auto start of pump on its normalisation.
Start the AC seal oil pump (One) 2 to 3 times with an interval of about 1
minute to vent out the air from system till seal oil pressure transmitters on TE
and EE show a constant value. If needed perform venting of pressure
transmitters.
Note: Ensure healthiness of EPB of pumps.
Observe various seal oil parameters as mentioned above.
- 42 -
Check changeover of pumps by stopping the running pump from UCB. Stand
by AC pump should take start if put on AUTO mode.
Observe seal oil pressure at various places as mentioned above.
Ensure normalisation of DC seal oil pump electrical supply at local starter
panel.
Check AUTO start of DC seal oil pump by stopping the running AC seal oil
pump and observe seal oil pressure at various places as mentioned above.
Start any AC seal oil pump and stop DC seal oil pump from UCB.
Put control of all seal oil pumps on AUTO mode from UCB.
4. SEAL OIL PUMP CHANGE OVER PROCEDURE:
Ensure opening of pump suction and discharge valve at local.
Start standby pump by following above procedure.
- Observe various seal oil parameters as mentioned above.
Check for any oil leakage.
Stop the running pump (main) and observe seal oil pressure at various places
as mentioned above and put its control in AUTO.
5. SEAL OIL PUMP ISOLATION PROCEDURE:
Take pump control in manual.
Ensure electrical isolation of pump.
Ensure mechanical isolation of pump by closing its suction and discharge
valve.
6. SEAL OIL VACUUM PUMP START-UP PROCEDURE:
Check that
- Electrical supply of pump is normal.
- Oil level in sight view glass of vacuum pump is normal.
- Drive belt of pump is intact.
- 43 -
Take vacuum pump control in manual & start vacuum pump.
Note: Ensure healthiness of EPB of pumps.
Open gas ballast valve & kept close shutoff valve (suction valve)
to avoid the formation of moisture condensation as the pump is in cold
condition.
Open shutoff valve after the pump has been put in service for
~ 30 mins. Pump must be warm to touch.
Use control valve ( bypass valve of pump) to adjust vacuum in seal oil tank to
approx. -0.6 to -0.8 bar.
Put control of pump in auto mode to facilitate auto operation of vacuum pump
on seal oil vacuum tank level high protection.
7. SEAL OIL VACUUM PUMP CHANGE OVER PROCEDURE:
- Start standby pump by following above procedure.
- Close shutoff valve (suction valve) of main pump by opening shutoff valve of
standby pump.
- Observe the performance of standby pump and adjust the seal oil tank
vacuum with control valve.
- Close the outlet valve of main pump and stop pump.
- Put control of main pump in auto mode.
8. SEAL OIL VACUUM PUMP ISOLATION PROCEDURE:
- Take pump control in manual.
- Ensure electrical isolation of pump.
- Ensure mechanical isolation of pump by closing its suction and discharge
valve.
- 44 -
9. SEAL OIL FILTERS CHANGEOVER PROCEDURE:
Change over the filter when DP across the filter is >0.6 bar.
Open vent valve of standby filter.
Open equalising valve and perform venting and filling of standby filter. Close
vent valve of filter after proper venting.
Turn rotary transfer valve to the standby filter side.
Close equalising valve.
NOTE: While opening the standby filter (choked) for cleaning ensure that
equalising valve is close to avoid spillage of oil.
10. CHARGING OF SEAL OIL COOLERS ON WATER SIDE:
Charge seal oil coolers on waterside when seal oil temperature reaches to
40ºC.
Ensure closing of both inlet and outlet valves of coolers.
Open vent and drain valve on water side of the cooler selected.
Gradually open inlet valve of cooler selected.
Close vent and drain valve when flow is continuous through them.
Control cooling water flow through cooler to maintain oil temp. by adjusting the
opening of isolating valve on outlet.
Rise in seal oil temp., when outlet valve on water side is full open, indicates
the need for changeover.
To avoid corrosion on the standby cooler,
- Ensure that inlet and outlet valve of cooler is fully closed.
- Vent and drain of cooler on waterside should be open to keep it dry.
- 45 -
11. SEAL OIL COOLERS CHANGEOVER PROCEDURE:
Ensure that cooler to be taken into service is properly vented on oil and
waterside.
Gradually open the cooler inlet valve, on waterside, and ensure proper venting
of cooler.
Close waterside vent and drain of cooler.
Open outlet valve on cooling waterside of cooler partially.
Note: Outlet valve to be opened according to cooling water temp.
Open oil equalizing valve of cooler and ensure proper filling and venting of
cooler on oil side.
Take cooler in service, from oil side, by turning the common wheel of threeway valve on oil inlet and outlet towards the cooler to be taken into service.
Clean the standby cooler on waterside and keep it as standby.
12. SOST VAPOUR EXTRACTOR FAN START UP PROCEDURE:
Check that
- Electrical supply of fan is normal.
- Freeness of fan in coupled condition.
- TS and ES brg vent line valves are open.
Note: Ensure healthiness of EPB of fan.
Start SOST vapour extractor fan from UCB.
Check following at local:
- DOR of fan is OK.
- Vapour is coming out from exhaust pipe.
- Open suction/discharge header drain line valves at 0 M for collection of oil if
any.
- 46 -
13. SOST VAPOUR EXTRACTOR FAN CHANGOVER PROCEDURE:
Start standby fan by following above procedure.
Check following at local:
- DOR of fan is OK.
- Vapour is coming out from exhaust pipe.
Stop running fan and kept it as standby.
14. SOST VAPOUR EXHAUSTER FAN ISOLATION PROCEDURE:
- Ensure electrical isolation of fan.
- Ensure mechanical isolation of fan by closing its suction and discharge valve.
- 47 -
MOT COOLERS
1. CHARGING OF COOLERS ON WATER SIDE:
PRE-REQUISITES:
DMCW/ACW pumps should be in service.
DM/ Aux. cooling water of Turbine should be charged.
CHARGING PROCEDURE:
Ensure closing of both inlet and outlet valves of coolers.
Open vent and drain valve on water side of the cooler selected.
Gradually open inlet valve of cooler selected.
Close vent and drain valve when flow is continuous through them.
Gradually full open inlet and outlet valve. Keep close watch on DMCW hdr
(suction/Discharge) pressure while opening inlet and outlet valves.
2. CHARGING OF COOLERS ON OIL SIDE:
PRE-REQUISITES:
MOT level should be adequate.
MOT centrifuging machine should be available/running for charging of lub. Oil
to MOT if required.
EOP/AOP/MOP should be in service.
- 48 -
CHARGING PROCEDURE:
Open oil vent of the standby cooler.
Open oil equalizing valve of cooler and ensure proper filling and venting of
cooler on oil side.
Ensure proper filling/charging of cooler by touching cooler body.
Ensure proper venting of cooler by touching vent line. Vent line should be
warm.
Note: Raise MOT level above normal before charging of cooler.
3. MOT COOLER CHANGEOVER PROCEDURE:
Gradually open the cooler inlet valve, on waterside, and ensure proper venting
of cooler.
Close waterside vent and drain of cooler.
Open standby cooler inlet valve, water side, to full.
Gradually open outlet valve on cooling waterside of cooler to full.
Open oil vent of the standby cooler.
Open oil equalizing valve of cooler and ensure proper filling and venting of
cooler on oil side.
Ensure proper filling/charging of cooler by touching cooler body.
Ensure proper venting of cooler by touching vent line. Vent line should be
warm.
After complete filling and venting of cooler, start cooler changeover by
gradually turning rotary transfer valve.
After changeover of cooler, observe Turbine Lub oil temperature for some
time.
- 49 -
Note: Raise MOT level above normal before start of changeover.
Observe MOT level during changeover, if required top up MOT.
4. MOT COOLER ISOLATION PROCEDURE:
Close standby cooler waterside inlet and outlet valve.
Open waterside vent and drain of cooler.
Ensure complete draining of cooler from water side.
Open vent valve of standby cooler on oil side.
No oil flow should be from vent line. Ensure it by touching.
Keep MOT centrifuge machine in service.
Open cooler drain valve on oil side and manual isolating valve on line
connected to centrifuge machine suction.
Note: Observe rise in MOT level, if required maintain MOT level by opening its
drain valve partially.
- 50 -
MAIN EJECTORS
A. MAIN EJECTORS CHANGEOVER PROCEDURE
a. Check the following, before taking standby ejector in service:
- Charging of ejector from condensate side. If not then charge ejector from
condensate side by opening inlet and outlet valves gradually. Keep close
watch on condensate flow.
- Ejector siphon should remain in charged condition.
-
Ejector drip to condenser valve should be open. If not then open it gradually
by keeping watch on condenser vacuum.
- Ejector condensate over flow line valve is open.
- Opening of vent line/chimney manual valve.
- Condenser airline manual isolating valve should be open.
b. Open ejector steam valve and watch condenser vacuum. Keep watch on
ejector steam header pressure.
c. Close steam valve of the ejector to be taken out from UCB and watch
condenser vacuum and condensate DO.
B. MAIN EJECTORS ISOLATION PROCEDURE
a. Close condenser airline manual isolating valve at ejector.
b. Close ejector drip to condenser manual isolating valve.
c. Ensure closing of steam line isolating valve and its electrical isolation.
d. Open ejector bypass line valve (condensate side).
e. Close condensate line inlet and outlet valve of ejector tightly.
- 51 -
CONDENSER VACUUM PUMP
A.
PRE- START CHECKS
1. Check that all PTW are returned.
2. Check the supply of vacuum pump motor, circulating pump motor and system
inlet valve.
3. Check for the tightness of stuffing box glands.
4. Check that the separator tank level is adequate and make-up water is available.
5. Check that the cooling water for heat exchanger is available.
6. The gas discharge line of separator tank must be fully open.
7. Drain valves of vacuum pump, separator tank and heat exchanger must be
closed.
8. Rota- flow meter shut off valve should be in closed condition.
9. Shut off valves of all indicators and switches should be in open condition
10. Gas inlet manual isolating valve must be in open condition.
11. Instrument air supply to control system is available.
B. VACUUM PUMP START-UP PROCEDURE
1. Check that separator tank level o.k. Permissive is available. If not then level
make-up solenoid valve must open till the permissive is available then it must get
closed.
2. Start circulating water pump.
3. Give start command to vacuum pump motor.
4. System inlet valve will open automatically when a set differential pressure
(>.03 ksc.) is reached between condenser vacuum and pump suction.
Ensure from local that inlet valve is fully opened.
- 52 -
5. When vacuum is established then check that condenser vacuum and vacuum
pump suction pressure values are matching.
6. Gas discharge should be measured from rotameter to assess air ingress in
condenser.
C. VACUUM PUMP CHANGEOVER PROCEDURE
1. Take standby vacuum pump control from AUTO to MANUAL.
(Vacuum pump SLC to be made OFF)
2. Start standby vacuum pump as per procedure mentioned above.
3. Change Vacuum pump selection from Main to Standby at control desk.
3. Give close command to inlet valve of Vacuum pump (main).
4. After inlet valve is closed, give stop command to vacuum pump motor and
circulating pump. Observe condenser vacuum for some time.
5. Ensure from local that system inlet valve is completely closed.
6. After completion of changeover process, Vacuum pump SLC should be made
ON.
D. VACUUM PUMP ISOLATION PROCEDURE
1. Shut down the vacuum pump.
2. Isolate the supply of vacuum pump motor and circulating water pump motor.
3. Isolate the supply of system inlet valve.
4. Close the isolating valve of separator tank level makeup line and heat exchanger
cooling water line.
5. Open the drains of vacuum pump, heat exchanger, separator tank and drain the
system.
- 53 -
CONDENSATE PATH CHARGING (Stage-1)
PRE-REQUISITES
• No permit is outstanding on condensate path.
• CEP is ready (atleast one).
• Hotwell is in filled condition( level adequate).
• All transmitters and switches of hotwell in service.
• No permit is outstanding on deaerator.
• Hotwell make up line is normal in auto and DM make up pumps running.
Activities to be done before charging Condensate path:
• Open MC-25 (CEP RECIRCULATION) and its upstream/downstream manual v/v
100%.
• Close MC-27(Condensate line drain) full.
• Close MC-15 & MC-16 (GSC inlet/outlet v/v)
• Open MC-17 GSC bypass v/v full.
• Open MC-7/8/9 and 10/11/12 (main ejector inlet /outlet v/v).
• Open vent of condensate suction header of ejector.
• Close the v/vs of SWAS sampling line ,dosing line ,dosing make up v/v,
condensor gland sealing v/v, LP bypass spray etc.
• Close main ejector inlet header v/v.
• Close MC-21 &MC-19 deaerator control v/v .
• Open MC-33(drain cooler & LPH -1 bypass v/v) , MC-36(LPH 2 bypass) &
MC-39(LPH-3bypass v/v).
- 54 -
• Close MC-31(drain cooler inlet) ,MC-32(LPH-1 O/L) ,MC-34(LPH-2 I/L) ,
MC-35 (LPH-2 O/L V/V) MC-37(LPH-3 I/L),MC-38(LPH-3O/L V/V).
• Open water box drain /vent, shell drain/vent of LPHs .
• Open deaerator inlet v/v.
• Close BFP suction v/v.
• Close deaerator drain v/v to UFT.
• Open deaerator overflow v/v (DW-99) .
CHARGING OF CONDENSATE PATH
•
Start one CEP.
• Observe the air release from vents.
• Close vent v/vs after ensuring the release of air from line.
• Keep the CEP running on re-circulation.
•Maintain the CEP discharge pressure 20 ksc by regulating re-circulation v/v .
• Maintain hot well level.
• Make the system stable.
• Crack open the main ejector inlet header v/v .
• Fill line up to deaerator control v/v .
• Close vent after full air removal.
• Open deaerator control v/v slowly and start deaerator filling
• Keeping CEP header pressure adequate and hot well normal.
- 55 -
CONDENSATE PATH ISOLATION (Stage-1)
PRE-REQUISITES
1. Machine is out of barring.
2. No requirement of condensate in deaerator .
3. Ensure that sump pumps are available.
4. Condenser vacuum is in killed condition.
ISOLATION PROCEDURE
1. Stop all running CEPs and electrically isolate the CEP breaker.
2. Open all drains in condensate line to atmosphere.
3. Open LPH 1,2,3 (water side and shell side) drain and vent.
4. Open drain cooler and GSC shell & water side drains.
5. Isolate DM make up line to hot well.
6. Isolate gland-sealing line from DM make up.
7. Open CEP suction header drain.
8. Open hotwell drain.
9. Observe the minus mtr level.
- 56 -
FEED WATER PATH CHARGING (Stage-1)
PRE- REQUISITES
•
At least one BFP lined up and ready for service.
•
Deaerator is in filled condition.
•
No PTW is pending on feed water line and FRS.
•
Condensate path is in charged condition and one CEP running.
ENSURE THE FOLLOWING BEFORE CHARGING FEED WATER LINE
•
FW-55 and FW-56 are closed and gagged condition.
•
R.H attemperation block v/v in closed condition.
•
S.H attemperation block v/v in closed condition.
•
P.R.D.S attemperation block v/v in closed condition.
•
Eco inlet v/v BF-42 & BF-42A in closed condition.
•
BF-35,35A low load capacity inlet in closed condition .
•
BF-36,36A low load capacity inlet in closed condition .
•
BF-33,33A full load capacity inlet in closed condition .
•
BF-34,34A full load capacity inlet in closed condition .
•
SWAS sampling line in closed condition .
•
FRS inlet header vent in full open condition .
•
Open FRS line drain and vent .
•
Open Eco.inlet header vent before BF-42 ,BF-42A to 100% .
- 57 -
CHARGING OF FEED WATER LINE
•
Start one BFP in re-circulation.
•
Keep FRS vent open till all air removed and line is completely charged .
•
Charge FRS flow transmitter etc .
•
Open manually bypass v/v of one FRS line (say inlet BF-35A) .
•
After draining and venting , open FRS line outlet bypass v/v (say BF-39A) .
•
Fill the line up to BF-42, 42A;properly vent the line till water starts coming
out without air.
•
Maintain deaerator and hot well level .
- 58 -
FEED WATER PATH ISOLATION
PRE-REQUISITES
•
No requirement of feed water in boiler drum.
•
Deaerator steam from PRDS is in isolated condition.
•
Deaerator temp. is well within limits (<100 C) .
•
Deaerator fill line from DM make up is in closed condition.
•
Ensure minus meter TG area sump pumps are available.
ISOLATION PROCEDURE
•
Stop all running BFPs if in service and isolate from electrical side.
•
Close BF 42,42A (isolate from electrical side).
•
Open drain ,vent before BF-42,42A .
•
Open Deaerator drain to UFT.
•
Ensure Deaerator vents are in open condition.
•
Open BFPs suction / pump casing drain.
•
Open BFPs line vent.
•
Open HPH-5,6 shell/water side drain and vent .
•
Open FRS drain and vent.
- 59 -
CW PASS CHARGING (Stage-1)
PRE-REQUISITES
• No PTW is pending on condenser and condenser is boxed up from water
side.
• CW pump is running on re-circulation.
• CW duct is charged up to unit(i.e. up to manual I/L valve at transformer
yard)
• Outlet gate at CT pump house is in open condition (i.e./L of CT fore bay)
• Steam for priming ejector is available.
ACTIVITIES TO BE DONE BEFORE CHARGING CONDENSER FROM CW
SIDE :
• Open drains and vents of condenser pass A and B.
• Open vents to priming ejectors in condenser pass A and B.
• Open priming ejector vent to atmosphere.
• Charge steam of priming ejector.
• Close condenser O/L valve fully.
• Open condenser I/L valve fully.
• Isolate ONLINE CONDENSER TUBE CLEANING SYSTEM.
• Keep minus metre TG sump pump ready for use.
- 60 -
CHARGING OF CW PASSES
• Close the duct drain valve at debris filter.
• Crack open the I/L valve in sump at transformer yard and then keep on
increasing as per requirement.
• Close the drains of pass A and B water box after water starts coming full
mouth.
• Close the vents of pass A and B to priming ejector when water starts
coming from vent of priming ejector which opens in transformer yard.
• Stop the steam of priming ejector.
• After completion of venting process, Gradually open CW inlet valve to full.
If required, start one more CW pump before charging of CW passes.
• Observe the water coming in CT fore bay.
• Gradually open CW outlet valves as per requirement.
ISOLATION OF CW PASS
PRE- REQUISITES
• Machine is out of barring.
• Condenser vacuum is in killed condition.
• Ensure minus meter TG area sump pump are available.
PROCEDURE
• Stop online tube cleaning system if running and isolate.
• Close transformer yard CW inlet v/v to 100%.
• Open condenser water box drain and vents.
• Open CW inlet/outlet duct drain in minus meter TG area.
• Close pass-A and B outlet valve to full.
- 61 -
VACUUM PULLING (Stage-1)
PRE-REQUISITES
• TG Machine is on barring.
• Vacuum breaker is in open condition.
• Seal steam available up to seal steam I/L valve (AS-51) with adequate
temp. (>180 C)
• Ejector steam available up to main and starting ejector.
• Condensate path is in charged condition.
• GSC is in charged condition from condensate side.
• GSC Exhauster fans available and in ready condition.
• AS 44,44A and AS 51,51A are in closed condition and available.
• All condenser connected valves are water sealed.
• Seal exhaust to GSC line to atmosphere is in closed condition.
• Main ejector is charged from condensate side.
• Siphons of main ejectors and GSC are in charged condition.
VACUUM PULLING PROCEDURE
• Open seal steam header drain to condenser.
• Open air line manual valve to main ejectors (CA 3,4,5) and motorized
valve to starting ejector (CA 7)
• Normalize GSC drip to condenser and ejector drip to condenser.
• Line seal steam exhaust to GSC.
• Open I/L valve of GSC exhauster.
- 62 -
• Start GSC exhaust fan.
• Open starting ejector steam I/L valve AS-23.
• Observe vacuum pulling whistling sound and air ingress from vacuum
breaker.
• Charge siphon of Vacuum breaker and close vacuum breaker.
• Observe whistling sound increases as vacuum starts building up.
• When vacuum reaches to -250 mmwcl charge seal steam to turbine
seal,then whistling sound will slowly stop.
• When vacuum raised upto -600 mmwcl,take one main ejector also in
service and open its steam valve.
• Further raise vacuum upto -800 mmwcl.
• Close seal steam hdr drain when adequate temp.>250 deg. cel. reaches.
VACUUM KILLING(Stage-1)
PRE-REQUISITES
• Boiler stop v/v is closed condition.
• All high-energy drains connected to condenser is in closed condition.
• Turbine MAL drains are closed and SLC of drain is OFF.
• All headers drip line connected to condenser is in closed condition.
• CEP is in running condition and exhaust hood spray available.
• CW water in condenser is available and charged condition.
- 63 -
VACUUM KILLING PROCEDURE
• Take out main ejectors/ Vacuum pumps.
• Open vacuum breaker.
• Observe condenser vacuum /pressure.
• Stop seal steam supply by closing seal steam control v/v manually and
close its manual upstream valve.
• Observe exhaust hood temp. of LP turbine .
• Stop GSC VEF and isolate it electrically.
• Open GSC steam line vent to atmosphere.
• Observe Turbine expansions and barring speed.
- 64 -
ACW TANK FILLING
Pre-requisites :
• ACW tank empty and cleaned condition
• No PTW pending
• TMD recorded clearance for ACW tank filling
• Both ACW pumps suction valve in closed condition
ACW Tank Filling Activities:
• Informed to running unit
• ACW tank drain valve closed.
• Level transmitter & indicator valves open
• ACW tank filling start through control valve CF 183 in controlled way.
• Observe tank level in UCB & local
• Check level alarms
• V.Low
700 mmwc
• Low
900 mmwc
• High
1340 mmwc
• V.High
1380 mmwc
- 65 -
AUX COOLING WATER SYSTEM
CHARGING PROCEDURE
Pre-requisites:
• No PTW pending on ACW pump, at least 01 ACW pump available.
• ACW tank level is adequate
• EPB of ACW pump in release condition, Power supply of ACW pump in
normal condition
• Raw water through PHE in charge condition.
Aux. Cooling water charging activities
• ACW tank filling control valve CF183 kept in auto
• Check ACW motor bearing temperature normal
• ACW suction & re-circulation valve open
• ACW line vent at PHE open
• Inlet & outlet valve of ACW in PHE open
• Start ACW pump and check the following:
- Motor current, bearing temperature
- Any abnormal sound from Motor/ pump
- Motor/ Pump vibration
- Pump Gland leakage
• Discharge valve of ACW pump open as per requirement of cooling water
- 66 -
• Air vent valve closed when water coming from air vent.
• ACW re-circulation valve closed.
ACW PUMP CHANGEOVER PROCEDURE
• No PTW pending on stand by pump
• Normalize ACW standby pump mechanically and electrically & release EPB
• Start standby ACW pump & check the following
- Motor current, bearing temperature etc
- Any abnormal sound from Motor/ pump
- Motor/ Pump vibration
- Pump Gland leakage
• If standby pump running normal stop the other ACW pump and put it as AUTO
standby.
ACW PUMP ISOLATION PROCEDURE
• ACW pump should be in stopped condition
• Standby pump de-selected
Electrical Isolation :
• Rack out the ACW pump breaker.
• Breaker locked and key kept in key box (UCB)
Mechanical Isolation :
• Suction & discharge valve closed
- 67 -
H2 COOLER BOOSTER PUMP START-UP
PRE-REQUISITES
•
DMCW / ECW pump is in running condition .
•
DMCW / ECW suction header is in charged condition .
•
H2 booster pump is coupled and ready for load trial .
PROCEDURE
•
Ensure that pump recirculation is in full open condition .
•
Ensure that pump discharge in full closed condition .
•
Normalise the supply of booster pump and put in local mode .
•
Start pump from local PB and observe the current , vibration , brg.temp.
rise , etc for smooth running , otherwise stop the pump .
•
Ensure full charging of Generator H2 coolers.(To be charged at TG at 600
rpm)
•
Gradually open pump discharge valve and observe pump suction and
discharge header pressure at local.
- 68 -
ACW BOOSTER PUMP START-UP
PRE-REQUISITES
•
ACW pump is in running condition .
•
ACW suction header is in charged condition .
•
ACW booster pump is coupled and ready for load trial .
PROCEDURE
•
Open the bypass v/v of H2 cooler inlet line .
•
Open vent vent near APH lub oil cooler at boiler side .
•
Start booster pump from local .
•
Release full air from top most vent at APH coolers and when line is
completely charged close it .
•
Keep booster pump running, if no abnormality is there.
- 69 -
H2 / ACW BOOSTER PUMP CHANGE OVER PROCEDURE
PRE-REQUISITES
•
Check mechanical side line up : inlet / outlet v/v in open condition ,
recirculation v/v in close conditon.
•
Check electrical side line up : electrical supply of pump is normal , EPB
is released.
PROCEDURE
•
Start the stand by pump from UCB / Local.
•
Observe the parameters like current / discharge pressure / vibration /
abnormal sound /brg.temp to be normal.
•
Stop the first pump and keep it available. Check the reverse rotation of
pump.
H2/ACW BOOSTER PUMP ISOLATION PROCEDURE
•
Perform pump changeover as per above procedure.
•
Close inlet / outlet valve.
•
Open line/pump drain valve .
•
Ensure electrical isolation of pump. Ensure elctrical isolation of suction
and discharge valve of pump in stage-3.
H2/ACW BOOSTER PUMP NORMALISATION PROCEDURE
• No PTW on pump is pending.
• Close pump drain valve.
• Gradually open pump inlet valve keeping pump vent open.
• After proper venting of pump, open its inlet and outlet valve. Observe
pump for reverse rotation and gland leakage if any.
• Ensure electrical normalisation of pump. Ensure elctrical normalisation of
suction and discharge valve of pump in stage-3
- 70 -
HYDROGEN COOLERS
A. CHARGING PROCEDURE
1. Ensure no PTW is pending on cooler
2. Ensure clearance is available for cooler charging.(Coolers to be charged at TG
speed 600 rpm)
3. Ensure DM cooling water system is charged
4. Open hydrogen cooler booster pump inlet and outlet valve
5. Keep eye on DMCW suction header pressure
6. Vent hydrogen cooler booster pumps
7. Open vent valve of all coolers (04 nos)
8. Crack open cooler DM water inlet valve
9. Wait until continuous water flow starts from all the vents
10. Slowly full open the inlet and outlet valves of cooler
11. Close the coolers vent valves
12. Open DMCW pump suction header vent valve for some time to eliminate any
trapped air before charging H2 coolers.
13. Start hydrogen cooler booster pump
14. Check booster pump suction and discharge pressure
B. ISOLATION PROCEDURE
1. Ensure clearance is available for cooler isolation
2. Shut down booster pump, if running
3. Close inlet valves of coolers
4. Close outlet valves of coolers
5. Open vent valves, if required
- 71 -
EXCITER COOLERS
A. CHARGING PROCEDURE
1. Ensure no PTW is pending on cooler
2. Ensure clearance is available for cooler charging
3. Ensure DM cooling water system is charged
4. Open vent valve of coolers (02 nos)
5. Crack open cooler DM water inlet valve
6. Keep eye on DMCW suction header pressure
7. Wait until continuous water flow starts from all the vents
8. Slowly full open the inlet and outlet valves of cooler
9. Close the vent valve
10. Open DMCW pump suction header vent valve for some time to eliminate any
trapped air
B. ISOLATION PROCEDURE
1. Ensure clearance is available for cooler isolation
2. Close inlet valves of coolers
3. Close outlet valves of coolers
4. Open vent valves, if required
- 72 -
HYDROGEN DRYER
A. START-UP PROCEDURE
1. Check that no PTW is pending on stand by H2 drier and Refrigerant gas
pressure in Dryer is adequate.
2. Now switch ‘ON’ 3-phase main switch provided on the panel board. Main
supply ‘ON’ lamp will glow.
3. There after press the ON/OFF switch provided on the Local panel board.
Hence, Compressor will start, and system will start cooling of H2 gas for
removal of moisture.
4. Open the Hydrogen gas inlet/outlet valve of dryer .The dryer system will
there after start extracting moisture. Drain the moisture from Manual drain
valve provided on the dryer.
5. Check the cut-in and cut-off temp. of dryer. Auto cut-in and cut-off
temperature of compressor should be 6°C & 2°C respectively
6. After taking the dryer into service, keep close watch on the Hydrogen
pressure (DROP RATE) and its Dew point.
B. ISOLATION PROCEDURE
1. Close the inlet and outlet valve of hydrogen dryer and drain out the
moisture.
2. Now switch off the compressor supply from on/off switch provided on the
Local control panel.
3. Isolate the main supply from the MCC. Main supply ‘ON’ Lamp Indication
at Local will become off.
- 73 -
GENERATOR STATOR WATER SYSTEM
A. STATOR WATER PUMP START-UP PROCEDURE
Before starting a pump ensure
1. All PTWs on stator water pump and system are cancelled
2. Fill expansion tank to normal level and maintain vacuum in it
3. Check the conductivity of stator water after coolers
4. Pump inlet and outlet should be opened. Ensure proper venting of pump
5. Cooler inlet and outlet should be opened. Ensure proper venting of cooler
6. Open all vents and gas traps etc to release air
7. Check healthiness of pump power supply and pump
Now start the pump
After starting the pump
1. Ensure proper venting of system
2. Adjust stator water flow (>21 cub m/hr)
3. Properly watch and maintain stator water I/L and O/L pressure, conductivity,
H2 / stator water DP etc.
B. PUMP CHANGEOVER PROCEDURE
Before changeover of pump ensure
1. Expansion tank level and vacuum is normal
2. Pump inlet and outlet should be opened
- 74 -
3. Check healthiness of pump power supply and pump
4. Stator water flow and pressure, H2 / stator water DP, conductivity etc are
normal
5. Now start standby pump
6. Check healthiness of pump, increase in flow and pressure
7. If everything is normal stop the running pump
8. Check stator water flow, pressure and DP, H2 / stator water DP
C. PUMP ISOLATION PROCEDURE
1. If PTW is to be issued then changeover the pump if required
2. Isolate the power supply of pump
3. Close inlet and outlet valves of pump
STATOR WATER COOLER
A. CHARGING PROCEDURE
Before charging the cooler from stator waterside charge the cooler from ACW
side with proper venting. Subsequently, follow the steps as mentioned below:
1. Start flushing the cooler from stator water side by crack opening its I/L valve
2. Open all vent and drain of cooler of stator water side
3. When clean water starts coming out from drain close the drain and allow
cooler flushing through vent
4. Measure the conductivity of stator water
5. If conductivity is OK, close the vent and equalize the pressure of both coolers
- 75 -
6. Slowly fully open inlet and outlet valves and keep close watch on stator water
flow, pressure and conductivity.
7. Adjust ACW water flow to cooler to get required stator water temperature
8. Closely watch the conductivity of stator water
B. ISOLATION PROCEDURE
1. Slowly close stator water inlet valve watching stator water flow
2. Slowly close stator water outlet valve
3. Observe stator water temperature, if required regulate the ACW flow of other
cooler
4. Close ACW side inlet and outlet valves
5. Open drain and vents
PARAMETERS TO BE MONITORED DURING NORMAL OPERATION
1. Check expansion tank level and vacuum
2. Stator water flow, conductivity, PH, Cu, DO
3. Open gas trap and ensure H2 is not coming with water
4. Check normal operation of pump/ motor
5. Standby pump should be in auto/remote
- 76 -
DEBRIS FILTERS
One in each CW inlet to condenser It removes the debris before condenser inlet of CW to CW outlet.
Pre-requisites :
• No PTW pending on debris filters
• CW pass of condenser in charged condition
• Discharge manual valve of debris filter in open condition
Operation of debris filters
It can be operated in auto or manual mode. Its normal position is at 90 degree .
Operating steps
• Discharge motorized valve open
• Debris filter on 90 – 120 degree
•
120 - 90 degree
•
90 – 60 degree
•
60 – 90 degree
• Discharge motorized valve closed.
• It takes 15 minutes to complete one cycle in auto mode
- 77 -