Wilden Pump & Engineering Co. - Manufacturer of air-operated double-diaphragm pumps.

Pump will not run

Check air inlet and filter for debris.
Connect a test lamp to the two wires which run to pump and ensure that the lamp cycles on and off. Ensure that the lamp voltage and current requirements are the same as Accu-Flo coil voltage and current requirements.
Make sure that the air valve manual override (small red know on front of valve) is switched to the "0" position.
Check pilot pressure vent at the top of the operator/coil assembly to ensure that it is not clogged.
Check for a worn out air valve. If air continually blows the exhaust in very large quantities, the air valve seals may be worn beyond their ability to function. In this case, the valve must be replaced.

NOTE: Before the valve is scrapped, it is possible that it may be saved by completely disassembling the valve, cleaning all components and relubricating the valve.

Pump runs but little or no fluid comes out.

Check that the discharge isolation valve is not closed.
Check that the electric signal is slow enough that the pump is able to complete each physical stroke before it is signaled to change direction.. The time required to complete the stroke is determined by a variety of factors which include fluid viscosity and head pressure. The shaft can be viewed if the muffler is removed to verify that the pump is (not on every model).
Ensure that air supply pressure is high enough to overcome application head pressure requirements.
Check for pump cavitation; slow pump speed down to match the thickness of the material being pumped.
Check for sticking ball check valves. If the material being pumped is not compatible with the pump elastomers, swelling may occur. Replace ball check valves and O-ring with the proper elastomers.
Check to make sure that all suction connections are air tight, and that the clamp bands are properly tightened.

Pump air passages blocked with ice.

Check for excessive moisture in compressed air line. As the air expands out the exhaust during the operation of the pump, water vapor entrapped in the compressed air can freeze and block the air passageways in the pump. If this occurs, it may be necessary to install a coalescing filter, an air dryer, or a hot air generator for the compressed air.

Air bubbles in pump discharge

Check for ruptured diaphragm.
Check tightness of clamp bands, and the integrity of the O-rings, especially at intake manifold.

Product comes out air exhaust

Check for diaphragm rupture.
Check tightness of piston plates to shaft.

Pump rattles.

Create false discharge head or suction shaft.

Solenoid buzzes or solenoid burnout.

Incorrect voltage, faulty or dirty solenoid.

Solenoid valve fails to shift electrically but shifts with manual override.

Incorrect voltage, defective coil or wiring.

Solenoid valve fails to shift electrically or with manual override.

Inadequate air supply, contamination, inadequate or improper lubrication, mechanical binding in the valve.

Valve shifts but fails to return.

Broken spring, mechanical binding.

Excessive leaking from air valve vent.

Worn seals in air valve.

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