Product Manual A

Maintenance
31609 A MTP4000-6000DZV/DZD Operating Manual 61
3. The valve stem assembly may be removed by a similar action of pin removal. Two cross-drilled holes in the
lower end of this part, with slightly separated center lines, accommodate accumulated tolerances in the
assembled linkage parts. In most instances the drill from which the clevis pin has been removed will be the
one to re-use on reassembly.
Linkage Replacement
1. Reverse the previous procedure steps.
2. When the linkage is correctly reassembled and fastened to the cover, the valve seat O-ring should seat
firmly when the float ball is raised to its uppermost position, and a 1/8 in. (3 mm) minimum gap should
remain between the two actuator arms. If the arms can come together, the valve may not be adequately
seating.
Strainer/Baffle
At factory assembly, the stainer is pushed onto the bottom of the priming chamber and is held in place by friction.
During normal operation this strainer can drop loose from the cone and rest on the slotted suction spool pipe. This
is NOT a problem. Air being evacuated from the suction piping can travel freely through the slots and around the
strainer.
Maintenance
There is no regular maintenance to be performed on the separator. However, there are precautions for operation
during freezing conditions. In freezing conditions, ensure that there is no ice in the separator chamber to impede the
separator float movement. Warm water can be poured over the separator or into the separator chamber through the
separator hose connection. When pumping in extremely cold conditions, ice may form on the separator valve seat,
preventing closure and allowing water into the compressor. Close observation must be maintained and the pump
shut down at the first signs of water coming from the compressor.
Note: During an initial re-prime, there may be liquid remaining in the suction spool above the slots. This may allow
brief misting out the discharge before the prime valve has closed. If at any other time during operation pumpage is
seen continuously exhausting from the compressor, the pump should immediately be shut down and the priming
chamber cover should be removed. Inspect the float assembly for any impediment to its movement. It should be able
to fully close the valve stem assembly to the valve seat. Also check the prime valve for any damage or debris.
DISCHARGE CHECK VALVE
The discharge check valve enables automatic priming of the pump by closing the air leakage path on the discharge
side of the pump. This allows the primer to pull the pump casing vacuum down sufficiently that atmospheric pressure
will push the check valve open and allow the flow of liquid through the discharge.
The presence of the check valve, as with any other fitting in the piping system, add resistance (pipe friction) to the
total head the pump must overcome during normal operation, and not just while priming for start-up. The amount of
this added friction varies with the rate of flow, as well as with pipe size. To determine the extent of the addition for a
specific performance point, refer to the flow rate charts beginning on page 43.
If the check valve disc should be prevented from completely closing due to debris or damage, the pump will not re-
prime. In such a case it will be necessary to remove the inspection cover and clean out the debris or service the valve.
Maintenance
The check valve requires no scheduled lubrication or maintenance. For service or inspection, the valve can be
serviced without disconnecting the inlet or outlet hoses.