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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> system underperforming https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1425255915 Message started by JohnD on Mar 2^nd, 2015, 12:25am

Title: system underperforming
Post by JohnD on Mar 2^nd, 2015, 12:25am

Outr Church hall has a 3" single pipe system; steel 6 foot rads and original boiler went in about 1965. It is now heated by a potterton cf100 kingfisher boiler, about 12 years old. Hasn't been used that much - say about 25 - 30 hours per week at most.

All has\ worked well until 18 months ago when we noticed it was taking 3 hours to heat to a decent temprature instead of the more normal 1 1/2 hours. It now sometimes takes even longer. The same firm that fitted it have serviced it regularly. They said the culprit wasn't the pump as this has been checked sand it is possible the system is silted up buy rust and is probably time expired. We have used fernox since the boiler was fitted - however it is just possible this was not added when we had an underground leak a few years ago (under a doorway - rest of the system is above ground) and cannot understand this unless the heat exchanger itsealf is furred up. it does seem to us that the rads and pipework are too large to furr up easily.

To replace the boiler will cost about £2500 and the rads and pipework as well very much more. Is it possible it is the gas pressure regulator within the boiler failing? If not what could it be? And yes, I know this is not an amateur job - we are just trying to clue ourselves in a bit as to what the problem might be.

Regards

John Davies

Title: Re: system underperforming
Post by thescruff on Mar 2^nd, 2015, 9:36am

Is it just a single pipe with both ends or the rad connecting to the same pipe ?, some pics of the rads and connections would help.

Is the pipe much hotter than the radiators ?

What valves do you have on the radiators ?

Title: Re: system underperforming
Post by JohnD on Mar 2^nd, 2015, 10:09am

It is indeed a single pipe with both ends of the rad connecting to the same pipe. Obso;ete these days. Rads have been bled.

Pipes and rads are much the same temperature as far as I can tell, and each rad seem about the same temperature as the next one.

Just standard 'taps'. Haven't been touched for years.

It is probably best to put in a modern system but the cost will be colossal for the amount the place is used.

THanks for your interest

John Davies

Title: Re: system underperforming
Post by thescruff on Mar 2^nd, 2015, 10:33am

Are the pipes connected at the bottom both end or is the flow connected to the top of the rad.

I would give the pipework a good flush out with a hose pipe include the boiler, however you can't flush the rads and these will need to be taken off and flushed individually with a hosepipe outside.

You could check the pump for blockage while it's drained down.

One pipe systems are still installed commercially and works well.

Title: Re: system underperforming
Post by JohnD on Mar 2^nd, 2015, 11:03pm

Both pipes connected to the bottom, I think.

Seems good advice - I'll pass it on to those responsible

Thanks

John Davies

Title: Re: system underperforming
Post by Headrush on Mar 21^st, 2015, 1:03pm

Have you checked the flow pipe from the boiler for temperature? It should be piping hot. If it's not then surely the boiler is at fault somehow. Maybe overheat stat is kicking in too early or main stat is malfunctioning..