Nova-Tech Pulsafeeder OMNI DC7 - Manual (Page 20)

20
7.4 Check Valve Removal & Reinstallation, Plastic Union-Nut
type
1. Disconnect the power source to the drive motor.
2. Relieve all pressure from the piping system, and take all precautions necessary to prevent
contamination to the environment and personnel exposure to hazardous materials.
3. Close the inlet and outlet shutoff valves.
4. Loosen the union nuts that hold the check valves in place. It is not necessary to completely remove
the nut.
5. Push the check valve assembly out of the front by inserting your finger or a tool into the clearance
hole at the back of the holder. Note carefully the position of the component parts, to assist in re-
assembly. Be aware that product may leak out as the check valve parts are removed.
6. 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 o-ring seat facing up and the chamfered edge
down.
The check assemblies must be pushed into the holder until they stop against the back surface.
Replace parts with new as required. Sealing o-rings should generally be replaced even if the
check components are re-used.
Figure 13, union-nut type check valve
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. Each union nut should be tightened only until the o-ring seal makes
good contact.
7. Carefully make sure that the check assemblies are in proper position, and tighten the union nuts.
8. Retighten any unions, flanges, or other process connections that may have been loosened previously.