Pipes banging as the pump starts and stops, gurgling inside the pump, vibration: where each noise comes from, and which ones the controller's soft start reduces.
Water pump noise in a building usually comes from one of four places: water hammer in the pipes, air inside the pump, the pump vibrating on its base, or the motor itself. Each has its own sign, and each has a different fix.
Banging in the pipes as the pump starts and stops
If the noise comes exactly as the pump starts or stops, a "bang" or a short shudder in the pipes, this is water hammer. When the pump suddenly starts at full power, the column of water in the pipe accelerates all at once; when it suddenly stops, the moving water stops all at once. Over time these shocks loosen joints and wear out taps and valves.
A mechanical pressure switch switches the pump on and off abruptly and can do nothing about this shock. The HYDROSET pump controller starts and stops the pump softly, and the time for each is adjustable:
| Parameter | Function | Factory setting | Allowed range |
|---|---|---|---|
| F11 | Soft start time | 0.2 seconds | 0.1 to 600 seconds |
| F12 | Soft stop time | 0.2 seconds | 0.1 to 600 seconds |
If you can still feel the shock, you can increase these two times a little and see the result. How to change parameters is in How to set a water pump controller.
Repeated banging means the pump is cycling
If the sound of the pump starting and stopping repeats several times a minute, the noise is not the main problem; the pump is switching on and off for no reason. The causes, namely a small gap between F1 and F2, the pressure vessel's air charge and leaks, are in Why does the water pump keep starting and stopping?
Gurgling or a gravel sound inside the pump
A sound like gurgling or gravel turning inside the pump usually means air or bubbles in the pump: the pump is air-locked or not enough water is reaching its inlet. Prime the pump and check the suction line. If the pump makes this noise and delivers no water, switch it off as soon as you can.
Vibration and constant noise
- Vibration through the floor or wall: a pump bolted directly and rigidly to the floor or wall passes its vibration into the building. Rubber mounts under the base and a flexible connector between the pump and the pipe reduce how much vibration is transmitted.
- Humming without turning: the motor has power but does not turn. Cut the power immediately and check the water pump capacitor.
- A harsher sound than before: if the motor itself has gradually got louder, the pump's bearings or impeller are probably worn and the pump needs servicing.
A quiet water pump for a flat
No pump is completely silent. How much noise a building's water system makes depends largely on the installation: rubber mounts, a flexible connector, a sound check valve, and soft starting and stopping. With these, even your current pump runs more quietly.
If you still have a mechanical pressure switch, the steps in swapping a pressure switch for a pump controller need no change to the pipework.
