Hot water flowing into expansion tank

[pablo06]

At the moment I only have my hot water on in an open vented system. When the hot water comes on hot water flows continuously into the expansion tank via the bent pipe that overhangs it. I had a plumber in and he turned down the setting on the pump. That seemed to cure the problem, but now it has come back. Also when the hot water comes on there is a rattling in some of the radiators. Any suggestions gratefully received.

 

[oilman]

Is it ONLY when the boiler/pump is running that the problem occurs?

 

[ChrisRoberts]

Sounds like a partialy blocked pipe. System will work ok but will pump over. Most likely the pipe near the cold feed is blocked.

 

[chrishutt]

The problem is presumably with the CH header tank, not the larger tank feeding the hot water cylinder. You may have a blockage in the pipework causing the low to come out of the vent pipe. Also likely that the system is corroded and needing cleaning.

 

[pablo06]

Yes, it only occurs when the system is switched on.

 

[pablo06]

Any ideas how this can be investigated and how the pipe could be unblocked? Would this be fairly routine for a professional?

 

[ChrisR]

It's entirely dependent on access and how much of the pipe is blocked. Sometimes the blockage is magnetic so you can try to find its extent that way, but it'll start at a tee a plumber will go straight to.

 

[wilhelm]

cup of tee . that is.

 

[Nige F]

"It started with a *iss.....who thought it would end like this"(smile you`re on camera) be careful who you let into your attic

 

[pablo06]

Thanks, everyone.