Problem |
Probable Causes |
Corrective Action |
Pump will not shut off
Note: Before trouble shooting automatic control, check to see that the pump
operates on manual control. To do this, create slight vacuum on breather tube
(near plug), then close off tube with thumb, plug into wall outlet. If the
pump works, proceed to check switch; if not, fault is in the pump or power supply. |
Diaphragm switch |
Replace switch |
Weak or hardened rubber diaphragm |
Replace rubber diaphragm |
Plugged vent tube |
Clear vent tube of any obstructions |
Dirt or sediment lodged between retainer ring and rubber diaphragm causing contacts to remain closed |
Clean area around rubber diaphragm |
Pump is air locked |
Shut power off for approximately 1 minute, then restart. Repeat several times to clear air from pump. If system includes a check valve, a 3/16" hole should be drilled in discharge pipe approximately 2" above discharge connections. |
Liquid inflow matches pump capacity |
Larger pump required |
Defective switch |
Disconnect switch, check 2/ohmmeter, Open-infinite resistance, closed-zero |
Loose connection in level control wiring |
Check control wiring |
Pump runs but does not discharge liquid |
Check valve installed backwards |
Check flow indicating arrow on check valve body to insure it is installed properly. |
Check valve stuck or plugged |
Remove check valve and inspect for proper operation |
Lift too high for pump |
Check rating table |
Inlet to impeller plugged |
Pull pump and clean |
Pump is air locked |
(See corrective action above) |
Pump does not deliver rated capacity |
Lift too high for pump |
Check rated pump performance |
Low voltage, speed too slow |
Check for proper supply voltage to make certain it corresponds to nameplate voltage |
Impeller or discharge pipe is clogged |
Pull pump and clean. Check pipe for scale corrosion |
Impeller wear due to abrasives |
Replace worn impeller |
Pump cycles continually |
No check valve in long discharge pipe allowing liquid to drain back into sump |
Install a check valve in discharge line |
Check valve leaking |
Inspect check valve for correct operation |
Sump pit too small for inflow |
Install larger sump pit |