Nova-Tech Pulsafeeder OMNI DC7 - Manual (Page 21)

21
7.5 Check Valve Removal and Reinstallation, Metal Tie-Bar type
1. Disconnect the power source to the drive motor.
2. Relieve all pressure from the piping system.
3. Take all precautions necessary to prevent contamination to the environment and personnel exposure
to hazardous materials.
4. Close the inlet and outlet shutoff valves.
5. Loosen the suction valve tie-bar bolts (4) and spring the suction piping slightly away from the head,
allowing liquid to drain. It may be necessary to loosen a union or flange.
6. Remove the suction check valve assembly by sliding it towards you, holding it together as a unit.
Note carefully the position of the component parts, to assist in re-assembly.
7. Loosen the discharge valve tie-bar bolts (4) and spring the discharge piping slightly away from the
head, allowing liquid to drain. It may be necessary to loosen a union or flange.
8. Remove the discharge check valve assembly by sliding it towards you, holding it together as a unit.
Note carefully the position of the component parts, to assist in re-assembly.
9. Disassemble both valves and check components for wear or damage. The seats should have a sharp
edge and be free from dents or nicks. Hold a ball firmly against the seat in front of a bright light and
inspect for fit, observation of light between the ball and seat is cause for replacement.
10. Reassemble both valves using new parts as required. Sealing o-rings should always be replaced.
11. Replace both valve assemblies onto the pump, taking care to ensure they are oriented correctly, with
the balls above the seats, and the seats oriented with the sharp edge up and the chamfered edge down.
Inserting the check valve assembly into the pump in the wrong directiom, or having the check seat
upside down, will prevent proper seals at the o-rings, decrease pump performance, and can cause
damage to the diaphragm.
12. Carefully make sure that the check assemblies are in proper position, and tighten the four tie-bar
bolts, using a star pattern, to a torque of 6 Ft-lbs (8 N-m).
13. Retighten any unions, flanges, or other process connections that may have been loosened previously.