Pulsafeeder Pulsa GLM DM7 - Manual (Page 20)

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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.