Ask a tradesman


Radiators - 3 work, 2 don't!

I had a new boiler installed in my flat but a lot of the pipework is 8mm and 10mm. there are 2 radiators which do not get hot at all. I don't think the rads are in a loop as there are lots of pipes coming through to the central point where the boiler pipes go to. Boiler fitter did a power flush on installation but it was hard work, then bled the rads but still no joy. He said the only option was to get new piping to the 2 that don't work but I want a second opinion as I've already paid out a lot for the boiler.

7 Answers from MyBuilder Plumbers

Best Answer

There is a small chance that the pipework could be simply air locked. Try shutting off the valves on the rads that do work. The theory being that the boiler / pump will push the air through to the affected rads. Then re bleed.


Answered 18th Mar 2011

Disconnect the pipe work to these rads one at time and check if there is water to them . Remember the system will be under pressure so there will be no need to disconnect them completely from the radiator merely loosen the union nut. if there is water or any sign of pressure behind the pipes then it can be one of two things, the valves need replacing or the radiators are blocked. If there is not water out of the pipes then unfortunately the only option would be to replace the pipe work as it would indicate that the existing pipes are blocked with sludge.


Answered 14th Mar 2011

Sounds like new pipes required, as all above, they sound like they are solid, i use 15 mm for rads. Get 3 quotes from other plumbers to compare price.


Answered 16th Mar 2011

when you power flush micro bore pipework all you do is move the sludge around and block the manifold its impossible to do a sufficient flush on 10mm and 8mm


Answered 8th May 2011

Hi there, i have been on several jobs where other installers have installed 10mm pipe work that go through the entire house. I was working on on the otherday that had the same problem. 10 rads and 3 of them are not working. i did everything i could to get them working, even powerflushed they system. in the end, i installed new pipework fromt the boiler to the rads and they worked fine. i looked at the old pipes and saw that they were completely blocked. i couldnt believe it, so whenever i do new installations now i always try and use the biggest pipesize i can.

I hope this is of some help to you




Answered 14th Mar 2011

Which to are not working did he power flush right. Has he try to see if the Rad valves are working. I take it he has connected back to old pipe work


Answered 14th Mar 2011



Answered 30th Mar 2011

Post your job to find high quality tradesmen and get free quotes

Can’t find an answer? Ask a new question

Question Categories