In most cases the noise will be caused by this pump operating at an excessive speed.
Boiler water pump noise.
If the noises continue after you have taken the previous actions there is a possibility that the problem may lie in the circulation pump.
Came out to the pump on the boiler making a weird noise.
Check the circulation pump.
Why a central heating pump might be noisy.
Otherwise you re likely to find it in the airing cupboard or under the stairs.
If the pump isn t already set to the lowest speed push the dial all the way to the left and wait to see if the humming noise stops.
Recirculating hot water pump noises duration.
Adventures in living 5 306 views.
If the humming stops and you want to keep the pump set at a lower speed just check that the radiators heat up properly and the boiler isn t cycling too fast.
In most cases the central heating pump can be found pretty close to the boiler so that it can begin pumping the water as soon as the boiler is done heating it up.