Noisy hot water pump

13 Jan 2011
Reaction score
United Kingdom
For some reason when our hot water starts heating, only sometimes, the pump makes a lot of noise when it comes on.

After a minute or so, when you can start to hear water, the noise stops and it just sounds like a pump.

It doesn't happen when the heating is on, and only happens a few times a week when the hot water comes on, not every time it comes on.

This is the pump...

Any idea what it could be?
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Could be a worn pump bearing. It'd be worth changing the pump anyway - that one draws as much as 105 watts of power all the time that it is running. A new Alpha2 will never draw more than 42 watts and will modulate down from that to match the load on your system. This will save you rather a lot on your electricity bills!
There's nothing to stop you doing it yourself if you have the confidence and tools
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Just seen the cost of a new pump, ouch.

Is there a way to replace the bearing to keep it going for a bit longer until I can afford to replace the pump or really not worth it?

I don't mind doing it myself unless it means draining the system or similar.
Unless ere are some gate valves eihr sde of the pump ( not in pic) then it will require draining to change, if the noise aint that bad leave it be
There is one valve, see photo below.

The noise is getting bad, our hot water comes on early in the morning and it has woken us up on occasion.

If it could be done then I'm happy to do it. I'll call a plumber though if it's going to be a big job.

Unless there are some gate valves either side of the pump (not in pic) then it will require draining to change, if the noise aint that bad leave it be

It has ball valve iso's either side.

Not the best though as they are notorious for leaking.
no, no DIY serviceable bearings in it, pump change it would be.

the ball valves may be ok, just a matter of trying them, prepare for leaks though when doing it. ideally partial drain to the pump level and swap for gate valves tho if you can.
I'd wager that there may be some restriction in and around that H section of pipework. While replacing the pump, I'd do a magnet check on the pipes and take the appropriate action.

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