Radiator Heating Issue *please help*

dbear

My mum recently had the majority of the radiators and pipes replaced as it’s an oldish house and was leaks etc. Since then the radiators will not heat up from the central heating system. They will heat in parts, different ones different times, totally randomly. They have all been bled and balanced multiple times. However, there is also a stove with a back boiler and when we light a decent fire the rads all heat up perfectly, every time. Is this some kind of a pump issue or something? The plumber doesn’t seem to know what to do and wants to dig up a load more pipes. The system heated perfectly before, just was to be updated because of leaks. I would really appreciate any suggestions of any other things to try first. The house has been freezing since November and I just want to help my poor mum!

brokenangel

So the radiator heat up from back boiler but not from boiler? Am I correct?

dbear

Yes, exactly!

brokenangel

https://www.boards.ie/discussion/comment/118738125#Comment_118738125

Ok, now in my house the boiler is on a different pump to the back-boiler/stove. Do you have separate pumps?

If the boiler is going is the water temp right? also are the water pipes red hot from the boiler but not from the pump? e.g. the pump is not pushing the water away from the boiler

John.G

https://www.boards.ie/discussion/2058236018/radiator-heating-issue-please-help

There will or should be two pumps, also 2 non return valves to stop the water re circulating to the "off" heat source, looks possibly like the NR valve on the gas/oil boiler is stuck open, it will look like this (below), give it a tap of a hammer, might just reseat it until replacement.

Poppet Type NRV.jpg

dbear

Thanks so much for your reply. Yes they are separate pumps. Water gets super hot sometimes when heats been on awhile. Not sure about pipes. Not there now to check but can tomorrow. If they are like that, it would show it was was the pump then and would be worth trying replacing that?

dbear

Brilliant, I’ll give it a go, thank you!

John.G

Should have said that its the NRV on the stove that may be stuck open, easy to test, switch on the oil/gas boiler and after a few minutes (assuming stove Off) feel the pipes at the stove, these should stay cool/cold.

Is it a gas or oil fired boiler?, if an oil fired boiler then you will be able to see the pump, ensure its running, if it has LEDs take a close up photo of it and post it, if a pump problem then the boiler will only fire for a minute or two and then cut out for another few minutes. If a gas boiler then if not a pump problem it should stay running continuously so watch for this, the pump may be external but unlikely, if so take a photo of this and post.

dbear

That’s what it was! Valve replaced now and all sorted. Thank you so much!!