1/2 In. VT Valve Flushing Procedure
For Normally Open, Normally Closed, or
Three-Way Valves
Kit: V-9999-660
O-Ring
Kit: V-9999-661
O -R in g
O-Ring
Groove
Body Cap
Figure 1a: Body Cap with
O-Ring
O-Ring
Groove
H os e F lush
A da ptor
Figure 1b: Hose Flush Adapter
with O-Ring
The procedure covered in this document describes the recommended method
to properly flush and clean out low capacity 1/2 in. VT style valves. The small
plug clearances typically found in low capacity globe style control valves could
make them inherently susceptible to plugging and sticking when particulate
debris, from an inadequately cleaned system, cannot pass through the valve.
These plug clearances are mandated by the valve Cv and precise flow
characteristics. If valves in a system exhibit characteristics associated with
plugging and sticking due to particulate debris, this flushing procedure may help
to alleviate the problem.
The procedure includes two methods, one method uses a body cap
(as illustrated in Figure 1a) to flush the valve particulates down into the system,
the second method uses a hose adapter (as illustrated in Figure 1b) to flush an
individual valve through a hose to an external source (i.e., a bucket or drain).
Refer to the specific sections for the proper procedures for Normally Open,
Normally Closed or Three-Way Valves.
Part No. 14-1065-9, Rev. © 1994 Johnson Controls, Inc.
1
Printed in U.S.A.
Diagnosing the Problem
Proper diagnosis of the problem is important before beginning any corrective
action procedures. The following steps provide guidelines for troubleshooting a
valve suspected to have “sticking” problems associated with particulate
contaminants.
1.
Measure the control signal at the actuator. Is the valve being commanded
to stroke, if so, in which direction? Is the valve stem moving?
2.
After addressing the above questions and the stem appears to be stuck,
properly disconnect the control air line and remove the actuator.
3.
Try to stroke the stem by hand. If it is stuck, carefully try and free it.
4.
Check for particulate contaminants:
•
With flow through the valve, debris in the system causes the stem to
stick, seize, or feel “gritty” throughout the travel.
•
With a Normally Open (Push-Down-To-Close) valve, the water flow
holds the particles suspended in the annular clearance between the
plug and the port wall. When the valve is stroked, the debris may
become wedged and the valve seizes. If the flow is stopped (such as
closing an upstream valve), the particles may drop to the bottom of the
valve and reverse travel will free the plug. To check this, stop the flow
by closing a shutoff valve upstream of the subject valve. Free the
stem and stroke the valve by hand. The stroke should feel smooth.
If flow is reestablished, the travel will again feel “gritty” or stick as a
result of the debris.
•
With a Normally Closed (Push-Down-To-Open) or a Three-Way valve,
the stem stroke may feel “gritty” or stick even with the system pressure
removed.
If the diagnosis indicates particulate contaminants are the root cause of the
sticking, refer to the flushing procedure included in this document.
Setup
This procedure can be followed independently on problematic valves or
concurrently on several valves. However, if practical, the recommendation is to
flush all valves concurrently when chronic system wide problems exist to ensure
that the debris is not recirculated to other valves.
•
2
Because the procedure for use with the body cap (V-9999-660 kit) involves
flushing the debris through the system, it is important to install the
appropriate filter or strainer to remove any foreign material from the
circulating water. The screen or filter should have a maximum opening
of 0.010 in.
•
Prior to starting, briefly read through the procedure to determine if any
other special equipment is required. Take the necessary precautions to
ensure that other equipment will not be damaged by this flushing
procedure.
•
Determine how many valves will be flushed concurrently, and ensure that
the appropriate number of body caps are on hand.
Normally Open (Push-Down-To-Close) Valve Flushing Procedure
B onnet
A sse m bly
F or reinstallation:
a pp ly pip e join t
com poun d to
body fac e.
M a gn et
Debris
Figure 2a: Normally Open Valve
with Magnet Inserted
Figure 2b: Normally Open Valve
with Valve Bonnet Assembly
To flush a Normally Open Valve proceed as follows:
Note:
These procedures do not require the removal of the stem and plug
assembly from the bonnet. Stem removal is not recommended since
packing damage may occur, which would require replacement.
Isolate the Valve
1.
Isolate the valve by closing the necessary upstream and downstream
shutoff and/or balancing valves. For reinstallation purposes, note the
position of the balancing valve so it can be properly repositioned later.
3
Remove the Actuator
1.
Electric actuated valves: Disconnect the power supply to the actuator and
isolate the supply wire as necessary.
Pneumatic actuated valves: Disconnect the air supply as necessary.
2.
Remove the actuator from the valve. It is not necessary to remove the
spring assembly from the stem on pneumatic actuated valves.
Remove the Valve Internals, Cap and Flush
Body Cap
Flush
H o se Flu sh
A d a pte r
F lu s h
Figure 3a: Normally Open
Valve Body with Body Cap Kit
1.
Figure 3b: Normally Open Valve
Body with Hose Flush
Adapter Kit
Bleed the pressure from the valve by opening a drain valve or slowly
loosening the bonnet, then remove the valve bonnet assembly
(as illustrated in Figure 2a). Take the necessary precautions to catch
any water that may be released.
Note:
These procedures do not require the removal of the stem and plug
assembly from the bonnet. Stem removal is not recommended
since packing damage may occur which would require replacement.
2.
Visually inspect the stem, plug, and valve port for damage. Some abrasion
may be visible on the plug and port. Minor abrasion will not hinder
performance; however, if the plug or port are severely gouged or if the
stem is bent, the valve must be replaced.
3.
Visually inspect the internal cavity of the valve for debris that has settled in
the bottom of the valve. Remove any debris with a small magnet inserted
through the port (the magnet on the end of a small screwdriver is ideal).
Even if debris cannot be seen, insert the magnet into the port of the valve
to attract any particles that may not be visible (refer to Figure 2a).
4
4.
Clean the pipe joint compound from the top face of the valve body and
mating face of the bonnet. Sealant may be washed or cleaned with
kerosene or other hydrocarbon solvents. Follow all standard safety
precautions while handling cleaning solvents.
Note:
5.
The chemicals used to remove the thread sealant can adversely
affect the U-cups (packing) and rubber seat disc. Take the
necessary precautions to prevent chemicals from coming in contact
with these components.
Apply a small amount of grease (included in the kit) to the O-ring and install
it into the groove in the body cap or hose flush adapter, as illustrated in
Figures 1a and 1b.
Body Cap (Figure 3a)
6.
Thread the body cap kit into
the body and hand tighten.
7.
Fully open all of the
appropriate isolation and
balancing valves and flush
the valve.
8.
Hose Flush Adapter
(Figure 3b)
6.
Thread the hose adapter kit
into the body and hand tighten.
7.
Attach a garden hose to the
hose adapter.
8.
Open the upstream isolation
valve and flush the valve
through the hose into a bucket
or appropriate drain. Close the
upstream valve and open the
downstream valve and back
flush in the same manner.
9.
Repeat this procedure as
required to ensure an effective
flush.
Inspect the system filter(s)
and/or strainer(s) as
necessary to remove the
debris from the system and to
verify that flushing was
effective.
Rebuild the Valve, Replace the Actuator, and Verify Proper
Operation
1.
After flushing, isolate the valve again by closing the necessary shutoff and
balancing valves.
2.
After the valves have been adequately isolated, bleed the pressure as
required, and remove the cap or hose flush adapter. Inspect the valve
internals for debris. Repeat the procedure for removing debris with a
magnet to ensure that all particles have been flushed through.
3.
Check to make sure that the top face of the valve and the mating face of
the bonnet are clean. Sparingly apply pipe joint compound to the top face
of the valve body as illustrated in Figure 2b. Do not use the O-ring for
permanent installation on the bonnet.
Note:
Do not apply pipe joint compound to the threads. This may cause
the pipe compound to drip onto the valve seat and cause shutoff
problems.
5
4.
Thread the bonnet assembly back into the valve and tighten to a torque of
approximately 75 ft.lb (102 N.m).
5.
Open the isolation valves and reset the balancing valves to their original
marked position.
6.
Inspect for leaks and stroke the valve by hand to verify smooth operation.
7.
Reinstall the actuator.
8.
Reconnect the electric or pneumatic supply lines, and verify proper
operation.
Normally Closed (Push-Down-To-Open) or Three-Way Valve
Flushing Procedure
For reinstallation:
apply pipe joint
compound to
body face.
B o tto m C a p For reinstallation:
apply pipe joint
compound to
body face.
Figure 4a: Normally Closed Valve
Low er Body
Figure 4b: Three-Way Valve
To flush a Normally Closed or Three-Way Valve proceed as follows:
Note:
6
These procedures do not require the removal of the stem and plug
assembly from the bonnet. Stem removal is not recommended since
packing damage may occur, which would require replacement.
Isolate the Valve
1.
Isolate the valve by closing the necessary upstream and downstream
shutoff and/or balancing valves. For reinstallation purposes, note the
position of the balancing valve so it can be properly repositioned later.
2.
For Three-Way valves: Disconnect and isolate the piping from the bottom
N.O. (Normally Open) port of the valve. If possible, flush some water
through the N.O. piping into a bucket.
Remove the Actuator
1.
Electric actuated valves: Disconnect the power supply to the actuator and
isolate the supply wire as necessary.
Pneumatic actuated valves: Disconnect the air supply as necessary.
2.
Remove the actuator from the valve. On N.C. (Normally Closed) and
Three-Way pneumatic actuated valves it may be necessary to remove the
spring in order to hold the valve open.
Remove the Valve Internals, Cap and Flush
Stroke the stem but
do no t remove the bonnet. Use the spring
retaining clip or actuator coupling to stroke the stem.
Body Cap Kit
Note: The body cap repair part
can be identified by the extra
round hub at the bottom.
Figure 5a: Normally Closed or
Three-Way Valve with Body Cap
Hose Flush
Adapter
Figure 5b: Normally Closed or
Three-Way Valve with
Hose Flush Adapter
7
1.
Bleed the pressure from the valve by opening a drain valve or slowly
loosening the lower body, then remove the valve lower body (refer to
Figures 4a and 4b). Take the necessary precautions to catch any water
that may be released.
2.
Using a flashlight visually inspect the stem, plug, and valve port for
damage. Inspection should also include the bottom cap of a 3-way valve.
Minor abrasion will not hinder performance, however, if the plug or port are
severely gouged or if the stem is bent, the valve must be replaced.
3.
Visually inspect the internal cavity of the valve for debris. Remove any
debris with a small magnet, as best as possible, without removing the stem
from the bonnet.
4.
Clean the pipe joint compound from the bottom face of the valve body and
mating face of lower body. Sealant may be washed or cleaned with
kerosene, or other hydrocarbon solvents. Follow all standard safety
precautions while handling cleaning solvents.
Note:
5.
8
The chemicals used to remove the thread sealant can adversely
affect the U-cups (packing) and rubber seat disc. Take the
necessary precautions to prevent chemicals from coming in contact
with these components.
Apply a small amount of grease (included in the kit) to the O-ring and install
it into the groove in the body cap or hose flush adapter, as illustrated in
Figures 1a and 1b.
Body Cap (Figure 5a)
6.
7.
Thread the body cap into the
body and hand tighten.
Fully open all of the
appropriate isolation and
balancing valves and flush the
valve. Stroke the valve
several times by hand to
ensure an effective flush. The
spring retaining clip or actuator
coupling adapter can be used
to stroke the valve stem.
Remove the actuator spring if
necessary.
Note:
8.
Hose Flush Adapter
(Figure 5b)
6.
Thread the hose adapter into
the body and hand tighten.
7.
Attach a garden hose to the
hose adapter.
8.
Open the upstream isolation
valve and flush the valve
through the hose into a bucket
or appropriate drain. Open
and close the valve several
times by hand. The spring
retaining clip or actuator
coupling adapter can be used
to stroke the valve stem.
Close the upstream valve and
open the downstream valve
and back flush in the same
manner. Remove the actuator
spring if necessary.
9.
Repeat this procedure as
required to ensure an effective
flush.
Do not open the piping
to the N.O. side of the
3-way valve, because
it is no longer
connected to the valve.
Inspect the system filter(s)
and/or strainer(s) as
necessary to remove the
debris from the system and to
verify that flushing was
effective.
Rebuild the Valve, Replace the Actuator, and Verify Proper
Operation
1.
After flushing, isolate the valve again by closing the necessary shutoff and
balancing valves.
2.
After the valves have been adequately isolated, bleed the pressure as
required and remove the cap or hose flush adapter. Inspect the valve
internals for debris. Repeat the procedure for removing debris with a
magnet to ensure that all particles have been flushed through.
Note:
The body cap is not a replacement for the bottom cap on
N.C. valves. The original bottom cap must be replaced or the valve
will not operate properly. The body cap repair part can be identified
by the extra round hub at the bottom (refer to Figure 5a).
9
3.
Check to make sure that the bottom face of the valve and the mating face
of the lower body are clean. Sparingly apply pipe joint compound to the
bottom face of the valve body as illustrated in Figures 4a and 4b. Do not
use the O-ring for permanent installation on the bonnet.
Note:
Do not apply pipe joint compound to the threads. This may cause
the pipe compound to drip onto the valve seat and cause shutoff
problems.
4.
Thread the lower body back into the valve and tighten to a torque of
approximately 75 ft.lb (102 N.m).
5.
Reconnect the N.O. piping on the 3-way valve.
6.
Open the isolation valves and reset the balancing valves to their original
marked position.
7.
Inspect for leaks and stroke the valve by hand to verify smooth operation.
8.
Reinstall the actuator.
9.
Reconnect the electric or pneumatic supply lines and verify proper
operation.
10
11
12