Cold Radiator

[louise2316]

Hi
Hoping that someone might have some experience in the following:

Boiler: EVO HE

Wireless Thermostat: Drayton RF2. Downstairs set to come on at 0610-0710 if temperature is below 20C and again from 1730-1100.

Radiators: 3 downstairs, 2 upstairs. 1 in each bedroom. Bedroom 2 has the boiler in it. All with thermostatic valves

The radiator in Bedroom 1 never gets more than luke warm even when the valve is on max and the other valves are lower. British Gas recommended a powerflush which was completed in the summer. The radiator in Bedroom 1 was replaced as it was corroded and after the work, the radiator in Bedroom 1 got warm and all appeared to be functioning properly.

There are pipes below the floorboards between Bedroom 1 and 2 which were not flushed.

However, the same problem appears to be happening again and the radiator in Bedroom 1 is getting lukewarm at best. Is it possible that the reason this is not working is that the pipes under the floorboards need to be flushed? I am hesitating on this as the radiator seemed to function properly after the system was flushed without this part being done.
I have a dad who helps me out with these things but, I think he is at a loss but, won’t admit it! Any advice would be much appreciated!

 

[kbdiy]

Why was that part of the system not flushed? Was is because of the corroded rad? When the rad was replaced was a new TRV fitted or the old one refitted? If the old one it could be that the pin (under the TRV head) is stuck only partially open and not allowing full flow through the rad. Usually tapping the pin/valve will free up a partial seizure and allow full flow.

If not then there could be obstruction in the pipework where it was not flushed. It would be worth disconnecting the rad and opening each valve into a bucket to test the flow from each. If it only trickles then pipework is obstructed and further investigation needed.

 

[louise2316]

Thanks KBDIY!
I will check to see if the valve is new and come back to you before removing the radiators... The pipes were not flushed between bedroom 1 and 2 as the pipes were under floor boards and a bed!

 

[kbdiy]

Sounds a bit odd to me. I understood powerflushing was normally carried out by substituting the flushing kit for the pump and flushing the entire system. Lots of heating installations have pipes under floors so don't really understand why yours was different. Otherwise the flushing is pointless, in so much as the crud left in the unflushed section will gradually circulate and deposit elsewhere, so not achieving its main purpose.

Who actually did the flush?

 

[louise2316]

The flush was recommended by British Gas but, sourced a private business to do the work. A lot of sludge was cleared. Apparently when two raditators (downstairs) were added to the system a few years ago by a previous owner the flush was not done.

The TRV is not a new one. British Gas and the company who did the powerflush said that it was fine.

Thank you so much for the tips. Will be checking the pin and testing the flow this weekend. Will report back...