Solar Heating Troubleshooting Charts Solar Hot Water, Pool and Spa Circulation Pumps 1. Do not handle a pump or pump motor with wet hands or when standing on a wet or damp surface, or in water. 2. The pump motor may be equipped with an automatic resetting thermal protector and may restart unexpectedly 3. Protector tripping is an indication of motor overloading as a result of operating the pump at low heads (low discharge restriction), excessive high or low voltage, inadequate wiring, incorrect motor connections, or a defective motor or pump. 4. If plastic or fabric hose is used for the suction piping, it should be of reinforced type so as not to collapse under suction. The suction piping should be the same size or one size larger than the discharge piping. 5. Do not use a globe valve or other restricting type of valve at the discharge. Globe valves seriously restrict the capacity of the pump; however, restricting the discharge of a centrifugal pump will not overload the drive motor. Pumping Symptom  Possible Cause (s) Corrective Action No liquid delivered  1. Pump not primed and/or air in the system 2. Speed too low 3. Air leak in suction 4. Discharge head high 5. Impeller plugged 1. Prime pump, purge air 2. Check voltage / change speed  3. Repair or replace 4. Lower the height 5. Clean out, add filter to system Not enough liquid delivered 1. Air leaks in suction 2. Speed too low 3. Discharge head too high 4. Impeller partially clogged 5. Not enough suction head 6. Impeller or casing damaged 1. Repair or replace 2. Check voltage / speed switch 3. Lower the height 4. Clean out / add filter to system 5. Increase suction head 6. Replace Not enough pressure 1. Speed too low 2. Air in liquid or leak in suction 3. Impeller damaged or partially plugged 4. Liquid has too much solid material 1. Check voltage and speed 2. Repair or replace suction line 3. Clean or replace 4. Add strainer Pump works for a while then loses suction 1. Leaky suction line 2. Air leaks in suction line 1. Repair or replace 2. Repair or replace suction line Motor runs hot 1. Voltage and frequency lower than rating 2. Defects in motor 3. Normal 1. Reconnect to rated voltage 2. Replace 3. Check for safety precautions Noise 1. Air in system 2. Loose pipes 3. Rotating assembly worn 1. Purge air from system 2. Add pipe clamp as necessary 3. Replace assembly Note: Not all pumps have the option of changing speeds. Return to Solar Repair Page