G M TREBLE LTD
Operating & Maintenance Instructions
For Single Pump Sealed System
Pressurisation Unit & Expansion Vessel
Model:
Serial No:
PH-1L
INSTALLATION
Fixing & Piping:
The Ph-1L unit and the system expansion vessel should be bolted down side by side, if
possible on to a firm level base.
The heating/cooling system should be connected primarily to the expansion vessel using a
minimum 1”/28mm diameter expansion pipe, for LPHW heating systems the pipe should
incorporate an anti-gravity loop where possible 2 metres high, with an air vent at its highest
point, then connected into the system return on the suction side of any recirculating pumps,
should they be fitted on the system return. This expansion pipe should be fitted with a
lockable or otherwise tamperproof isolation valve, with a drain cock fitted on the expansion
side of the isolation valve, to facilitate setting up and future servicing of the equipment.
A minimum ¾”/22mm diameter delivery pipe from the PH-1L unit, fitted with a further
lockshield isolation valve, should be run to “tee” into the 1” expansion pipe on the expansion
tank side of the system isolation valve.
A 15mm diameter cold water supply pipe should be connected to the ½” ball float valve on the
PH-1L unit feed water tank.
Take care to ensure that all pipework is adequately supported to prevent any undue strain on
the connection and prevent the ball float valve from “bouncing”. The system high and low
pressure fault switches should be mounted together and their ¼”BSPM connections piped into
a further 2tee” in the system expansion pipe.
Electrical Connections
A single phase electrical supply and earth should be connected to the switch/fuse on the PH-1L
unit, preferably fed from the contactor starter having a motor overload set at approximately
(2.8amps). when no starter is incorporated on the PH-1L, the power supply should not be
interrupted by any time clock which may be used to control the boiler or chiller. In addition,
wiring connections should be made from the boiler/chiller control circuit to separate TBV high
and low pressure fault switches to interrupt boiler/chiller operation in the event of a pressure
fault.
PRE-START CHECKS
Note: If a G.M Treble commissioning engineer is used to put this equipment into
operation then the following paragraphs need not be followed, skip to “Normal
Operation”.
Expansion Vessel
Preferably before the system is filled with water but in any case with the system expansion
pipe isolation valve closed, fit a hose pipe to the expansion pipe drain cock to discharge to the
nearest drain, open the drain cock and allow any water to escape. Check the air cushion
pressure on the expansion valve by using a standard tyre pressure gauge on the Schrader
valve normally located beneath a black plastic cap on the top of the vessel and if necessary
adjust it to match the desired cold fill pressure.
Most expansion vessels are shipped with a higher air cushion pressure than the average
system will require, some air will therefore usually need to be released, however if a higher
than usual pressure is needed then an oil-free air or nitrogen source will be necessary.
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PH-1L Unit
Unless otherwise requested, all PH-1L units are preset on test in our factory for a
nominal cold fill pressure of 1.0 bar.
Open the ¼” Easyprime valve on the top of the pump body, before turning on the cold water
supply to the feed tank, allowing the tank to fill, check that the ball float valve has closed and
stopped running before closing the Easyprime valve, the pump should have now been primed.
Check the air cushion pressure on the accumulator vessel at the top of the unit in the same
manner as the expansion vessel, this should be set at 0.8 bar.
With the PH-1L discharge valve open, the drain hose in place and with the expansion tank
drain cock open, switch on the pump at the switch/fuse, the pressure should begin to rise on
the pressure gauge and the water should run from the drain hose. Depending on the
resistance through the drain hose, the pump may build up sufficient pressure to switch itself
off briefly before restarting again, but in any event allow it to run for a minute or so to clear
away any remaining air. Finally check the pump switching pressures. With the discharge valve
slightly open the pump will start at approximately 0.9 bar, run for a few seconds and will stop
at approximately 1.1 bar.
With the discharge valve completely closed should the pump fail to build up pressure and stop,
switch it off and re-vent it by opening the Easyvent valve for a few seconds, close the valve
again then retry.
If the cold fill pressure does not correspond with your requirements, refer to “Adjusting Cold
Fill Pressure” below.
When satisfied with the pressure setting the expansion tank drain cock can be closed and the
PH-1L discharge isolating valve opened, the pump will the probably start and run for
somewhat longer than previously, before building up pressure and stopping.
Adjusting Cold Fill Pressure
Should it be necessary to make any adjustment to the “standard” cold fill pressure setting of
1.0 bar, proceed as follows:
Switch off the PH-1L pump at the switch/fuse, with the expansion pipe isolated from the
heating/cooling system open the drain cock to allow any water stored in the expansion tank
and the PH-1L accumulator to empty until the pressure gauge reads zero.
Check the accumulator air cushion pressure by using a standard tyre pressure gauge on the
Schrader valve located beneath the black plastic cap on the end of the accumulator and if
necessary adjust it using oil free compressed air or nitrogen until it is 0.2 bar below the
desired cold pressure.
Roughly set the pump control pressure switch Range (RH) scale to the desired cold fill
pressure, then with the drain cock still open and the PH-1L discharge isolating valve slightly
open switch on the switch/fuse and observe the pressures at which the pump starts and stops,
until a setting 0.1 bar either side of the required cold fill pressure is reached.
High & Low Pressure Fault Switches
Once the correct cold fill pressure has been established in the expansion pipe the pressure
fault switches may be set; with the power supply to the switches isolated the top covers of
both switches can be removed after loosening their retaining screws, allowing the main covers
to be pulled off.
The Differential (LH) scale adjustment should be first be set to minimum on both switches,
then the high pressure switch Range (RH) scale adjusted to a setting of 0.5 bar above the
calculated final working pressure or 0.3 bar below the safety valve lifting pressure, whichever
is the lower. After rechecking that the correct cold fill pressure is still being maintained, check
if the low pressure switch has operated by confirming that the end of the operating lever on
the bottom left of the switch is in the high position, if it is not wind the Range (RH) scale
adjustment anti-clockwise it clicks “up”. Then wind the adjusting screw clockwise until the
switch operates again, finally turn the screw a further ½ turn to achieve the correct setting.
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The covers and lids may then be refitted and the power supply restored to check that the
boiler/chiller is able to operate and any fault/normal lamps operate correctly.
INITIAL START-UP
System Filling:
The system boiler/chiller and pipework must be completely filled with water before running the
recirculation pumps, normally this can be done by back filling using a hose connection with an
approved double check valve, though the pressurisation unit pump is continuously rated and
may be used to assist with this process if desired, though it may prove to be slower.
If a hose is used the system should be filled until a pressure of approximately 0.2 bar below
the desired cold fill pressure has been reached, when the expansion pipe system isolation
valve to the pressurisation equipment can be opened to allow the PH-1L unit to top the system
up. All pipework high points should be vented to remove as much as possible. The PH-1L unit
will ensure that the system is kept topped up.
Starting Up:
Once the foregoing procedures have been carried out it is permissible to start the
heating/cooling system circulating pump, since it is almost certain that some air will still be
present in the pipework this can be released from system high points either manually or by
automatic air vents if fitted, by occasionally stopping the circulating pump.
The pressurisation equipment is now functional.
OPERATION
Normal Running:
The PH-1L should always be left powered up and supplied with water, it will then be able to
operate at any time to ensure the system pressure never drops below the minimum cold fill
setting.
Expansion and contraction of the water with heating/cooling is accommodated by the
expansion vessel, as the system water temperature rises it is displaces into the expansion
tank, resulting in a general system pressure rise. The extent of this rise will vary with
expansion vessel size and operating temperature but working pressures between 1½ and up
to twice the cold fill pressure can be considered quite normal.
The expanded pressure can be seen on the pressure gauge of the PH-1L unit, but it should be
noted that the pressure indicated on the system circulating pump delivery gauge will be
somewhat higher than this.
During normal heating/cooling system operation pressurisation pump activity should be
minimal, unless there is any significant water leakage, the PH-1L pump will seldom be seen
running, and then only briefly when the system is cooling down.
MAINTENANCE
Maintenance is confined to checks made on the air cushion pressures of the PH-1L
accumulator and the heating/cooling system expansion tank, both tasks should normally be
carried out annually. The pump requires no lubrication but a visual check should be made for
any signs of leakage or any unusual sounds when running.
To check the accumulator and expansion tank air cushion pressures, shut down the heating
system, turn off the PH-1L at the switch/fuse, close the heating system expansion pipe
isolating valve, fit a hose on the drain cock and empty the contents of the of the expansion
tank to drain until the PH-1L pressure gauge falls to zero and the flow stops.
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Remove the air valve cap on the end of the accumulator and the cap on top of the expansion
tank, and using a standard tyre pressure gauge check the air cushion pressure and check with
the figures indicated on our commissioning report (if commissioned by G M Treble) or the
figures below if the set-up is as our standard factory set-up:
Accumulator air cushion pressure -
0.8 bar
Expansion tank air cushion pressure -
1.0 bar
If either pressure is found to have fallen below their respective figure, reflate to the correct
level using a suitable oil free or nitrogen supply.
When the air pressure have been restored, close the drain cock, remove the hose, replace the
air valve covers and reopen the system expansion pipe isolating valve before switching the
switch/fuse back on. Depending on the circuit pressure a PH-1L pump may run to restore the
correct minimum operating pressure.
IF THE AIR CUSHION PRESSURE IS VERY LOW OR ABSENT
Normally after draining the expansion tank and accumulator their air cushion pressures will
only be a little below the correct level, unless this check has been neglected for some time.
If the air cushion pressure is found to be very low a further check should be made on all vessel
connections, covers and around the Schrader valve fitting for possible leaks, this is best carried
out with soap/water solution or leak detector after reflation, any revealed leaks then being
rectified.
It the air cushion pressure is totally absent, and particularly if the air discharges from the drain
valve when reflation is attempted or water discharges from the Schrader valve, then
diaphragm failure is possible. A new diaphragm may need to be fitted.
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FAULT TRACING
MAKE-UP PUMP
CYCLES ON/OFF
RAPIDLY
Drain the accumulator and expansion tank and check that the air
cushion pressures are set to the recommended level, any substantial
under (or over) pressure will affect the frequency of pump operation.
Check for debris or damage to non-return valve fitted to the PH-1L
discharge connection.
MAKE-UP PUMP
WILL NOT RUN
Check the power supply to the switch/fuse and that the correct
5 Amp fuse is fitted and not blown.
Check the system is not already up to pressure.
Check that the feed tank level is adequate.
Check that the pump is free to turn by removing the cooling fan cowl
& turning the fan by hand.
Check that the pressure switch is functioning by operating it
manually.
MAKE-UP PUMP
WILL NOT START
Check that the switch off pressure indicated on the foregoing page is
being reached on the pressure gauge.
Check that the pressure switch is functioning by operating it
manually.
Check that the pump has not lost its prime, re=prime if necessary.
HIGH PRESSURE
FAULT
Expansion tank air cushion pressure too low or too high.
Drain the expansion tank and check that its air cushion pressure is
set to the recommended level.
Heating/cooling system temperature is too high.
System has been manually filled to an excessively high pressure.
LOW PRESSURE
FAULT
PH-1L pump is not switched on.
Switch fuse has blown.
Pump has lost its prime.
GM TREBLE LTD
New Street
Parkfields
Wolverhampton
West Midlands
WV4 6AN
Tel: 01902 333111
Fax: 01902 340941
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