Radiator problem

[Bob Eager]

We've been having a bit of a problem with the CH, and either it's got worse or we are just noticing it more now the weather is colder!

Downstairs radiators are working fine - in fact they seem rather too hot, if anything.

One upstairs radiator is stone cold, although the feed pipe to it (right up to the valve) is hot-ish (convection I guess). The other upstairs rads take a long time to heat up, and are not as hot as they used to be even if we set the house stat to maximum.

None of the rads have TRVs fitted.

I have checked that the pump is running - it appears to be, and both output pipes are hot.

The feed and expansion tank has about 2 inches of water in it. If I push the ball arm down, water flows in OK.

There is a thin trickle of hot water coming from the pipe positioned above the F&E tank; nothing dramatic.

Ideas, please?

[Set Square]

Have you bled the offending rads?

Have you tried temporarily turning off the hot rads downstairs? If so, do the upstairs rads then get hot? If so, the system needs *balancing* as per the FAQ at

[Bob Eager]

I knew I'd forget to something!

I'm getting nothing (apparently) but water from the bleed valves, so I assume they are OK. But tips on bleeding would help, if there's more to it than that.

been touched, I'm not sure...but if there is a reason, then I'll have a look.

(BTW, I did read the FAQ first...hence me trying to cover all the things I'd tried and forgetting to say the most obvious!)

[Set Square]

Well no - you open the valve. If air comes out (hissing sound) you keep it open until water comes out instead. If water comes out when you first open it, you close it PDQ!

In your first post, you hinted that perhaps nothing had *actually* changed - but just that you were noticing it more because of the cold weather.

If balancing doesn't fix the problem, you've got either a blockage in the upstairs pipes or an air lock. But try balancing first - it's easier!

[Bob Eager]

Well, it's a steady stream so I guess it's not that!

Yep...but it was working last spring, with all rads generating the right amount of heat...

Yes, I'm afraid it's a blockage or an air lock...will have a look.

So, how to get rid of an air lock?

BTW, what about the thin stream into the F&E tank? Im assuming that there is excess pressure due to the air lock/blockage and that it causeing a slight pump over...

[Set Square]

You can sometimes do it by closing the valves on all but one radiator - possibly accompanied by turning the pump up a notch, if it has speed control - thus forcing all the pump output along one leg of the system. Once it's cleared, it usually keeps going.

If that doesn't work, you may have to drain it, and re-fill it from the

*bottom* - i.e. forcing water from the mains in through a low level drail c*ck.

There shouldn't be *anything* coming out of the vent pipe under normal cicumstances. If it does it constantly, either the pump speed is too high or the fill and vent pipes are not connected into the flow pipe correctly in relation to each other and/or in relation to the pump. You'll need to address it before long - but get the rads working first, and it might *just* cure itself.

[Bob Eager]

Yes, I had that thought while discussing it with SWMBO earlier.

I'd thought of draining it, but not refilling from the bottom. Worth a go.

Thanks!