How to Troubleshoot a Grundfos MQ Pump

The Grundfos MQ is a compact, self-priming multistage centrifugal pump designed for domestic water supply. The pump is best employed at depth not exceeding 26 feet. The pump is operated by a control panel on top of the unit. When water is needed, the pump starts automatically, and a built-in pressure tank powers the unit. Do a little troubleshooting by looking for cracked or leaking suction pipes, clogged non-return valves and insufficient pressure in the tank.

Step 1

Check the water supply suction pipe for damage or obstructions, if the pump does not start. Run a supply of cold water through the pump, if the unit does not start due to overheating. Inspect the electrical box for blown fuses and tripped breakers. Ensure that the top point of the discharge pipe and the pump does not exceed 50 feet. The pump could be in an alarm condition. Reset the unit by pressing the "On/Off" button once. Press the button one more time to start the pump.

Step 2

Check the pipework for leaks or damage, if the pump will not stop running. Repair the pipework as necessary. Inspect the non-return valve for blockages. Clean the valve as needed.

Step 3

Check that there is adequate pressure in the pressure tank, if the pump starts and stops too frequently.

Step 4

Ensure that the ground connection is connected to the pump according to local regulations, if the pump gives out electric shocks.

Step 5

Drain the pump through the drain hole and loosen the union nut on the discharge pipe, if there is a risk of frost damage. Fill the pump with liquid before starting it again.

Step 6

Clean or replace the internal non-return valve, if the pump starts when no water is consumed. Have a service technician install a new valve.