Watts LF919-QT-FS, Инструкция по установке, эксплуатации и ремонту

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5
Servicing the First and Second Check Valves
WARNING
!
Depressurize valve before servicing.
No special tools are required to service the series.
Before servicing, make sure the water is turned off or shutoff
valves are closed.
1. Close shutoff valves up and downstream of the valve.
2. Using an appropriately sized wrench, loosen the check
valve cover. Unscrew the check valve cover and lift it off.
3. Remove the spring.
4. Lift out the disc holder assembly from the body of the valve.
5. To reverse the seat disc, unscrew the disc screw and dis-
assemble the disc washer and disc rubber from the disc
holder assembly. Reverse the disc rubber so the opposite
face is showing.
6. Assemble the disc screw through the disc washer and disc
rubber, and screw it into the disc holder.
7. To replace the seat module, pull the seat module out of the
body by gripping at the reinforcement ring. Replace the seat
module with the new seat by placing it into the body seat
bore.
NOTICE
When the cover is tightened in step 12, the cover is
engaged with the seat module properly.
8. Insert the disc holder assembly back into the seat module.
9. Replace the spring ensuring that it seats properly on the
disc holder.
WARNING
!
The first check valve has a heavyweight spring. The second
check valve has a lighter-weight spring. When reassembling
the check valves, install the correct spring into the correct
check valve.
10. Place the cover onto the spring with the internal guide on
the cover positioned inside the end coil.
11. Screw the cover onto the valve body.
12. Tighten the cover using the appropriately sized wrench.
13. Service the second check valve using steps 2 to 12.
14. Slowly open shutoff valves.
Check Disc Washer
Check Disc Screw
Check Seat
Check Seat
O-ring
Cover
Cover O-ring
Check Spring
Check Disc Rubber
Check Disc Holder
Check Assembly
Troubleshooting
SYMPTOM CAUSE SOLUTION
Check valve fails to hold
1.0 PSID minimum
Debris on check disc sealing surface Disassemble and clean
Leaking gate valve Disassemble and clean or repair
Damaged seat disc or seat O-ring Disassemble and replace
Damaged guide holding check open Disassemble and clean or replace
Weak or broken spring Disassemble and replace spring
Chatter during flow conditions Worn, damaged or defective guide Disassemble and repair or replace guide
Low flows passing through
mainline valve
Mainline check fouled Disassemble and clean
Meter strainer plugged
Damaged mainline seat disc or seat
Disassemble and replace
Broken mainline spring
DRAFT
10. Place the cover onto the spring with the internal guide on 10. Place the cover onto the spring with the internal guide on
12. Tighten the cover using the appropriately sized wrench. 12. Tighten the cover using the appropriately sized wrench.
13. Service the second check valve using steps 2 to 12. 13. Service the second check valve using steps 2 to 12.
Troubleshooting Troubleshooting
DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT
CAUSE
Check valve fails to hold Check valve fails to hold
1.0 PSID minimum 1.0 PSID minimum
Debris on check disc sealing surface Debris on check disc sealing surface
Leaking gate valve Leaking gate valve
Damaged seat disc or seat O-ring Damaged seat disc or seat O-ring
Damaged guide holding check open Damaged guide holding check open
Weak or broken spring Weak or broken spring
Chatter during flow conditions Chatter during flow conditions Worn, damaged or defective guide Worn, damaged or defective guide