How do I know when the diaphragm is ruptured?

The most obvious symptom is the appearance of fluid in the air exhaust outlet. The pump starts to run erratically, the flow rate drops and the outlet pressure becomes inconsistent. An unexpected increase in air consumption may also indicate a diaphragm rupture.

How often should the diaphragm be changed; what does its lifespan depend on?

The diaphragm does not have a fixed lifetime; it depends on the number of strokes, working pressure, cycle speed and abrasiveness of the fluid. It fatigues more quickly in fast running and high pressure pumps. A stroke counter is used to predict the life; it is replaced without waiting at the first sign of wear (decrease in flow rate, increase in air consumption).

What are the most common causes of AODD pump failure?

The most common failure is diaphragm wear/tear. Second most common is air-side (air distribution valve) failure, almost always caused by dirty or humid air - so a filter-regulator (FRL) unit is essential. The third common problem is ball valves not fitting properly in the seat; adding a strainer to the suction line reduces this.

How to store a pump that is not used for a long time?

Before long term storage, run the pump with clean water or a compatible solvent to remove fluid from the internal surfaces. Store in a cool, dry place to prevent diaphragm cracking. A short run test is recommended every 6 months.

Why does the air distribution valve (exhaust) ice up?

Compressed air cools as it expands from the pump to low pressure (Joule-Thomson effect); when the exhaust temperature drops below 0°C, the moisture in the air condenses and forms ice. Common in humid environments. Solution: install a filter-regulator-lubricator (FRL) in the inlet line, reduce the air pressure, upgrade to a higher pump size and run it slower, or divert the exhaust to a remote point.

What should I keep in stock for spare parts?

Critical spare parts: diaphragm set, ball valves, valve seals, O-ring set and air distribution valve seal set. Pumpport supplies wet-side and air-side spare parts kits on series and model basis.

Pump Maintenance Guide – Preventive Maintenance and Troubleshooting

Maintenance Plan

Maximum Pump Lifetime with Regular Maintenance

Air diaphragm pumps are relatively easy and low-maintenance machines, but when neglected they can lead to unexpected downtime, such as diaphragm rupture, valve blockage and air valve failure. The most common failure is diaphragm wear, followed by air side failures, almost always caused by contaminated or humid air.

Preventive maintenance at regular intervals not only extends pump life but also prevents unplanned production downtime. This guide explains maintenance intervals and what to do at each maintenance step by step.

Every shift: air filter, FRL and lubricant check
every 500 hours: ball valve and seal inspection/cleaning
every 1000 hours: diaphragm inspection (wear/swelling)
Dirty/humid air = most frequent source of failure → FRL unit required
Long-term storage: flush pump interior with neutral liquid
If there is a risk of dry running: add automatic stop system

Common Faults

Pump Problems and Solutions

Pump Not Working

Check air pressure and line. Air distribution valve may be clogged or frozen; install dehumidifier filter.

Low Flow Rate

The valve seat or ball may be contaminated. Remove and clean or replace the valves. Air leakage also reduces flow rate.

Fluid Leakage

The diaphragm may be damaged or torn. If fluid is visible on the air side, the diaphragm should be replaced immediately.

Excessive Noise/Vibration

Too high air pressure or loose connections cause vibration. Reduce pressure, check fixing screws.

Maintenance Schedule

Preventive Care Calendar

December	To be done	Objective
Each shift / per day	Air filter, FRL and lubricant check; leak and noise listening	Polluted air = most frequent source of failure
500 hours	Ball valve and seat cleaning; connection tightness check	Preventing flow drop and leakage
1000 hours	Diaphragm examination (wear, swelling, crack)	Change plan before rupture
Annual	Air distribution valve (ADS) service; full wet-side + air-side kit	ADS is the most frequently serviced part
Before storage	Wash pump with neutral liquid; store dry and cool	Aperture cracking and residue prevention

Maintenance Questions

Pump Maintenance
Questions

: The most obvious symptom is the appearance of fluid in the air exhaust outlet. The pump starts to run erratically, the flow rate drops and the outlet pressure becomes inconsistent. An unexpected increase in air consumption may also indicate a diaphragm rupture.
: The diaphragm does not have a fixed lifetime; it depends on the number of strokes, working pressure, cycle speed and abrasiveness of the fluid. It fatigues more quickly in fast running and high pressure pumps. A stroke counter is used to predict the life; it is replaced without waiting at the first sign of wear (decrease in flow rate, increase in air consumption).
: The most common failure is diaphragm wear/tear. Second most common is air-side (air distribution valve) failure, almost always caused by dirty or humid air - so a filter-regulator (FRL) unit is essential. The third common problem is ball valves not fitting properly in the seat; adding a strainer to the suction line reduces this.
: Before long term storage, run the pump with clean water or a compatible solvent to remove fluid from the internal surfaces. Store in a cool, dry place to prevent diaphragm cracking. A short run test is recommended every 6 months.
: Compressed air cools as it expands from the pump to low pressure (Joule-Thomson effect); when the exhaust temperature drops below 0°C, the moisture in the air condenses and forms ice. Common in humid environments. Solution: install a filter-regulator-lubricator (FRL) in the inlet line, reduce the air pressure, upgrade to a higher pump size and run it slower, or divert the exhaust to a remote point.
: Critical spare parts: diaphragm set, ball valves, valve seals, O-ring set and air distribution valve seal set. Pumpport supplies wet-side and air-side spare parts kits on series and model basis.