One new radiator is cold

[Northamptonredboy1]

Hi all. Maybe someone can shed some light on this problem. I had a new radiator (downstairs kitchen) fitted about four and a half years ago after a kitchen refurbishment. Its quite a large upright double. After the heating has been on for about 3 hours, only the top of the radiator is feeling barely lukewarm. It doesn`t have thermostatic control valves fitted just ordinary on/off valves which are both fully open. One valve gets quite hot when the heating is on. I`ve bled it and the water flows freely and clean. How can I get this rad to produce more heat ( at least the same as the other rads in the house ) I will just mention this - the central heating pipework to the rads is 15mm plastic/copper. When the kitchen work was done, the plumber used 10mm plastic feed from original pipes in the ceiling to the problem rad. Should this have been 15mm ? Is the 10mm pipe restricting the flow of hot water? Thanks in advance for your replies.

 

[Harry Bloomfield]

First step, search this site for mentions of radiator balancing.

 

[ScottishGasMan]

First quick test, if you have TRVs on most other radiators, turn them all right down (while the heatings on)

You may be lucky, and just have a bit of an airlock which should push through and result in the radiator being nice and toasty.



1. If it doesn't heat up to what you expect, then you may as well stop here, as no amount of balancing is fixing it, you have a flow rate issue, very possibly blockages in the plastic microbore feeding it.

2. If it heats up and stays hot once the other TRVs are turned all back on, then it was an airlock, happy days.

3. If it heats up but slowly cools back down once the other TRVs are turned back on, then it may be a case of balancing the system as suggested, although if it worked before and nothings changed, then chances are its still something starting to block up the pipes to it, or potentially a failing boiler pump.