Note:

The circulating pump motors are very quiet when they run. The way to tell is by feeling a small vibration through the pump motor casing as they run. The large screw on top of the pump is a bleed screw, fitted to allow any air in the pump to be bled away. Central heating pumps do not prime themselves, therefore any air that is inside can only be removed by bleeding. Loosen the screw slowly until the hissing air stops and then tighten back up again.


If you ever have the need to change the circulating pump in your particular central heating system it is good planning to make a couple of notes prior to starting. If you are not confident to do this job, then, call a professional service like Woolwich Plumbers. Like checking and noting down the direction of flow markings on the pump and pipework, also make sure that the replacement pump is exactly the same as the models can vary quite considerably. Even take photos. A Woolwich Plumber can identify, supply and fit a central heating pump.


1). Isolate the power to the central heating at the consumer unit or fuse box to make sure the direct electrical feed to the pump is off as they always have a constant live supply.

2). Close off the spindle operated water valves that sit either side of the pump. The circulating pumps only turn in one direction and have a flow arrow marked on the casing to help when the pump is being installed or replaced (as stated before).

3). Unscrew the terminal box lid and remove, exposing the connections. With an electrical tester confirm that there is no voltage at the terminals. There is also a dial/screw fitted on the pump case, so that the pump speed can be manually adjusted.

4). Once disconnected, undo the nuts on the pipe and remove the pump. Carry out the work and replace in your own time in reverse.