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by carter-admin 22 Jul 2019

Did your air-operated diaphragm pump fail recently? Whether they are old pumps or brand new, sometimes these diaphragm pumps can still cause problems. Typically, the issues are due to wear and tear, or operator issues, as these components undergo high-quality checks before being shipped out and hence manufacturer defective products are very unlikely to reach you. Check if your issue is one of the below:

Pump Fails To Cycle

There are several possible reasons for this to happen. The air valve may be stuck or dirty, in which case it needs to be disassembled and cleaned using filtered air. Check to see if the valve ball is severely worn out, or perhaps wedged in its seat, as the ball and seat may need to be replaced, or a pressure relief valve may need to be installed if the ball is wedged due to over pressurization. Also, see if the dispensing valve is clogged and needs to be cleared.

Pump Cycles Or Fails To Hold Pressure At Stall

Check the valve balls, seats or o-rings in case they are worn out. If so, they need to be replaced.

Pump Operates Erratically

The suction line might be clogged, there may be sticky or leaking balls, the diaphragm (or backup diaphragm) may be ruptured, the exhaust may be restricted, pilot valves may be damaged or worn, air valve or air gasket damaged, or the air supply may be erratic. Replace, clean or clear these components as necessary. If there is the icing on the exhaust muffler, switch to a drier air supply.

There Are Air Bubbles In The Fluid

A suction-line or diaphragm shaft bolt may be loose, or an inlet manifold damaged. Check also the seal between manifold and seat, and o-rings, if they are damaged. Other things to check are diaphragm (or backup diaphragm) is ruptured and needs to be replaced. If the pump is cavitating, reducing pump speed or suction lift may help.

Pump Air Valve Freezing

This is because of excessive moisture in the compressed air. You need to install a dryer, or hot air generator, for compressed air. Alternatively, you may consider using a filter to remove the water from the compressed air in some applications.

Pump Exhausts Excessive Air At Stall

The air valve block, o-ring, plate, pilot block, u-cups, or pilot pin o-rings may be worn out. Do also check the shaft seals if they need to be replaced.

Premature Diaphragm Failure

Check for diaphragm cavitation, you may need to enlarge the pipe diameter on the suction side of the pump or move it closer to the product. The diaphragm plates may be installed incorrectly too, confirm this with the operation manual. Also if you have been starting up the pump at full pressure, it’s recommended to start up pumping slowly.

If none of the above suggestions yield any results, it’s time to call in a reliable pump repair and support professional. Carter Pump has had success as leading experts in plunger pumps since 1897. Contact us today for expert advice and consultation for your pump needs.