cold radiator, expansion tank filling, dodgy heat exchanger

[traprain]

Our central heating system has usually worked ok in our 18 yr old house. But now we seem to have a number of problems, maybe someone here can tell me whether these problems are inter-related. The system we have is complicated by the fact that the ch circulates through a heat exchanger for our swimming pool. There is also though another gas boiler and pump that also feeds into the pipes leading into the heat exchanger - so in effect we have two boilers on the system - one is a Potterton and the other a Mexico. The problems are

- one radiator in the house does not heat up unless all other radiators are switched off
- swimming pool temperature is low,although pipes from ch system to and from heat exchanger are very hot
- there is a constant flow of water into the expansion tank and condensation forming in the loft

The BG engineer said he thought power flushing - at £500. Don't fancy that, but it does seem likely that sludge might gather at the cold radiator and the heat exchanger - both being the lowest points of the system. I'd be grateful for any thoughts, especially if anyone knows how or whether a heat exchanger can be cleaned out or whether it would need power flushing.

Thanks in advance

 

[oilman]

If you have got away with little or no maintenance for 18 years, you are lucky. It sounds like the BG man is reasonable in suggesting a powerflush. He has seen the system and I haven't, so I couldn't say what it ought to cost. The powerflush will attend to the heat exchanger to some extent. £500 over 18yrs is around 60p a week, not bad.

 

[ChrisR]

Agree entirely, but this
" there is a constant flow of water into the expansion tank and condensation forming in the loft
"
usually indicates that there is also a design fault exacerbated maybe by sludge.