The Comfort Submersible Pressure Pump 6000/5 automatic isn't working properly. What could be the problem?

Malfunctions and faults with Submersible Pressure Pump 6000/5 automatic are usually due to there being dirt on the check valve. The check valve needs to be free from contamination if this pump is to start and stop properly. This is the only way that this device can achieve optimum efficiency once it has been commissioned and thus enable error-free automatic operation. Suspended particles, sand and dirt in the water can settle on the check valve and cause it not to close properly. This causes a malfunction. With the Comfort Submersible Pressure Pump 6000/5 automatic Art. No. 1476, the check valve can be removed for cleaning or replacement without loss of warranty. Refer to the detailed description in our Service information about cleaning the check valve on Submersible Pressure Pump Art. No. 1476