2 Cold radiators upstairs

[Lostking]

The radiators in 2 of my bedrooms don't work. One is a single rad and has a thermostic valve on it (actually it has one on both the inlet and the outlet to the rad and both valves are in the max position). The other rad is in a bedroom with two rads, each of which has a thermostatic valve. The rad at the front of the room works fine but not the one at the back of the room. This rad appears to be downstream of the other rad. The problem is that the two radiators that don't work properly barely get luke warm and only at the top, but from about 4" - 5" down they are cold. Service engineers have tried rebalancing (but I think only a quick job) and one said it looked like an old single pipe system and the hot water was taking the easy route by not travelling through the rads. I am on an annual service contract with British Gas for the central heating but I would appreciate some ideas before calling the engineer out again. I wondered if the rads might be bunged up with sludge and needed flushing. Alternatively would new radiators be a solution? The house is 4 bedroom detached. The rest of the rads in the house work OK.

 

[moogwai]

if it's on a single pipe system you wouldn't really get results by powerflushing as the engineer said the water will just fly past the rad and you may find the water may heat rad a little bit.
my advice would be to put the money you was thinking of laying out for the flush towards upgrading the pipework to a 2 pipe system.
i have tried to powerflush single pipe systems before and gave up because of the above reasons.
alternatively you could take every rad off and flush them manually and see how that goes....but ultimately i would be looking at upgrading pipework.

 

[Billy Bob Bob]

agree with that convert to 2 pipe 1 pipe systems dont work,they were the idea in the early days and are rubbish

 

[WHPES]

1 pipe systems were designed for gravity circulation such as from back boilers and never originally intended to be pumped.