Cold Radiator

[Kroma]

Hi,

We had 'a man' round to remove the radiators in our lounge and dining room prior to decorating as they were 'loose'. It was discovered that the lounge radiator was cold just before this but a large amount of sludge came from the pipe upon removal so we guessed that this was to blame (we are new in the house so have no idea of the previous history).

When the decorating was finished, the radiators were re-hung but something broke on the dining room rad. The lounge radiator was now working fine. A date was made for the dining room radiator to be sorted out.

Unfortunately 'the man' forgot to come!

In the meantime, a leak appeared from a radiator valve upstairs. This was fixed promptly (although the white 'knob' broke in the process).

Today, 'the man' returned to finish the job on the dining room radiator. Apart from managing to empty the system into the fishpond (sorry fish!) everything seemed to go ok. This evening the dining room rad was warm and the lounge radiator was stone cold. We phoned 'the man' who suggested that we turn off a couple of upstairs radiators to release trapped air. This worked for the dining room radiator which is now hot. We then discovered the top of the bathroom rad was only warm but this was fixed by bleeding it.

We are now left with the situation that the upstairs radiators are fine, the kitchen radiator appears to be at about 80% heat, the lounge radiator is stone cold (it was working yesterday) and the other downstairs radiators are fine.

Any ideas as to what could be the problem with the lounge radiator? It's freezing!!!!

Thanks in advance,

Daz

[John Rumm]

It sounds like your system is in need of balancing (and also by the sounds of it a good clean and desludge!).

The first is easy enough to do with a bit of time:

sludge issue may be more of a problem however:

Hall has posted a detail account of how to carry out a system flush without the need for professional power flushing on a number of occations. This thread might be a good starting place:

also that flushing the system may require you to rebalance after - so do that second!

[Set Square]

As others have said, you're going to need to balance your system very soon, and de-sludge it fairly soon (although I would wait until the end of the winter for de-sludging if possible).

It is distinctly possible that your immediate problem is caused by an airlock. I would guess that you have solid floors downstairs so that the pipework cannot go under to floor but has to come down the wall from above for each radiator. Is this correct? It's very easy to get airlocks in the pipes to individual radiators with this setup. Before doing any bleeding, make sure that there is some water in the small fill and expansion tank in the attic (not to be confused with the large cold water header tank) and that its ballvalve is working properly. Then bleed all your radiators until water comes out of each one.

If you've still got a cold radiator, turn off all other radiators - both up and down - and turn up the pump speed temporarily to try to get water flowing to this cold radiator. If that doesn't work, you need to bleed each of the pipes connected to this radiator separately. Turn off one valve, and bleed a couple of litres of water out of the bleed hole. Then turn the valve back on and turn off the other one, and repeat the exercise.

When everything is working, turn all rads back on and put the pump back to its normal speed. Then balance the system.

[mcbrien410]

I flush my system about every two years. I turn off all radiators except one, this is generally an upstairs or highest radator. Then I turn the C/H pump to the high speed. It has a high and a normal speed. Then connect a hose pipe to the drain c*ck and poke the other end down a drain. Then open the drain c*ck and observe the water coming out to see the colour. Make sure the header tank is working and refilling the system as it drains. I usually allow ten minutes of clear water to flow out before closing that radiator and opening the next one. Repaet the process for each radiator in turn. I generally take a couple of weeks for the C/H water to completely de-gas/air itself so you'll have to bleed the rads for a while. Do this in the summer if possible.

Chris.

[Set Square]

That *may* work - but you have to make jolly sure that the ballvalve in the header tank can keep with with rate at which water is coming out of the drain c*ck - otherwise you'll starve the pump of water, with potentially expensive consequences.