33
DEPA
®
Air Operated Diaphragm Pumps
Fault
Possible cause
Remedy
6.0 Troubleshooting
Pump running, no delivery
Insufficient pumping capacity
Pump slows down, stops,
restarts
Reduced flow, stronger
pulsation
Product from muffler
Air in product
After filling the line
pump standstill
Pump draws in air
Suction valve closed
Suction capacity exceeded
Valve ball and seat on suction side worn
Muffler clogged
Air inlet filter clogged
Insufficient air supply
Pipelines blocked
Viscosity too high
Icing of the control valve
Valve ball on suction side
blocked
Diaphragm cracked
Diaphragm cracked
Air pressure too low
To high viscosity
Viscosity too hig
Seal the suction line
Open valves
Change the arrangement
Replace seats and balls
Clean or renew
Clean or renew
Check supply line
Clean
Change conditions
Use dry air
Supply the air with anti-freeze
Use a heavy-duty muffler
Ensure movability of valve ball
Replace diaphragm
Replace diaphragm
Increase air pressure