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1044131-06
5-7
Troubleshooting
Minimizing Pressure Deviations
Use the following guidelines to minimize pressure deviations.
Air Supply
Correct sizing and installation of the pump air supply system will reduce pressure
deviation problems. One indication of an inadequate air supply is excessive needle
Fluctuations of 0.35 bar (5 psi) or less are normal. Fluctuations above 0.35 bar (5 psi)
indicate a restricted air supply.
If it is inconvenient or expensive to install a larger air supply line, an air accumulator
can be installed at the pump. This will minimize the air pressure drop that occurs when
the pump reverses at the end of each stroke and ensure an adequate air volume during
pump changeover.
Air Exhaust
can be caused by high cycle rates at high air pressures, by a moisture laden supply air,
If the pump needs to be operated at high cycle rates and air pressures to maintain the
Another way to reduce ice build-up and exhaust noise is to exhaust the air into a large
common pipe manifold fabricated from 3- to 4-inch PVC pipe.
Correcting Siphon Problems
Use the following guidelines to isolate and correct siphon problems.
Cavitation
A large percentage of pump problems are the result of siphoning problems or cavitation.
Pressure variations can be caused by restricting the suction or siphon side of the pump.
When the pump does not fully prime on the up stroke, the pump will race or dive on the
and pressure spike is created. This hydraulic hammer also reduces packing, plunger, and
siphon check valve life.
simplest way to avoid cavitation problems is to provide a positive pressure at the pump
inlet. This can be accomplished by one of the following methods.
• Elevate the material supply, above the pump if possible.
• Immerse the pump inlet (use bucket or drum mount kits).
• Use a positive pressure supply system to feed the pump. Normal supply pressures are
• Use ram (elevator) mounted pumps, inductor plates, or follower plates.
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