Have removed radiator, need help!

[loumc]

Hi, we have removed a radiator in order to decorate behind it. We turned the lockshield valve off fine, but the other end has a thermostatic valve, which we turned to OFF thinking this would cut off the supply to the radiator.

However now the radiator is removed, there is still water coming from this valve, I realise now from looking at the forum that turning the TRV to OFF doesn't necessarily cut off the supply.

My question is, should we just allow the system to fully drain, (we have no stop ends available) or should we somehow try and turn the TRV off? Boiler is turned off etc. If we allow the system to drain how do we go about refilling it when the rad is back on?

 

[JohnD]

Have you got a combi boiler (which probably has a filling loop, and a pressure gauge by the boiler) or have you got a system with a small Feed & Expansion Tank in the loft?

If you have a combi, then the leak will allow the pressure to drop, after which (if you don't put any more water in) the dripping will stop. The boiler will not work until you restore the pressure.

If you have a F&E tank, whose purpose is to top up the water in the system, then the system will never empty, and the drip will never stop, unless you shut off the supply to the F&E tank. Close all the other radiators. The whole system probably contains 20 gallons of water.

Go up to the DIY shed tomorrow and buy some stop ends that look as if they will fit on the TRV.

If you have an F&E tank, also buy a couple of conical rubber bungs that you will find in the "plumbing tools" section.

If you end up draining the system, then you will need to refill with a Corrosion Inhibitor, otherwise all the radiators will rust away from the inside and you will get sediment which will cause blockages. In this case you may as well use a chemical cleaner before refilling. Sentinel and Fernox are good brands and you will find them at your plumbers merchant or DIY shed.

You might consider putting the radiator back on to stop the dripping overnight.

 

[loumc]

Thanks so much for the speedy reply!

We have a combi, the dripping has now pretty much stopped as you say, and the pressure gauge shows 0.

Does this mean the system has drained fully? Do we need to use the corrosion inhibitor that you mention?


Cheers!

 

[JohnD]

No, the system has not fully drained, it has just lost all pressure, so no more water will come out (unless you open the other tap).

What colour was the water, and did you get any black sediment out of the radiator when you tipped it up to empty it into your bucket?

 

[loumc]

The radiator water was black, and the last bit was a bit sludgy (when we tipped the radiator to one side). What does this mean?!

 

[JohnD]

That means you already have sediment, so it would be a good idea to flush it out, use a chemical cleaner, and refill with an inhibitor. If you are taking all the rads of for decorating, you will get most of the loose sediment out by taking them into the garden and squirting a hose through.

After that, use the chemicals. You can get them in cartidges with a nozzle that you can squirt into a rad though the bleeding hole (best to do this before refilling).

 

[loumc]

OK, thanks for the tips- just to put my mind at rest, are we OK to leave the rad off for now (considering we probably won't be able to get stop ends tomorrow as its easter sunday!)?
How do we get water back into the system once the rad is back on ( a lot of water came out!) and how do we repressurise it? Sorry for all the questions!!

 

[JohnD]

you can leave the rad off, but you won't have any hot water as the boiler will not run until it is repressurised (probably best to leave it switched off). As long as the rad is off, it will lose pressure. The boiler will have a filling loop, probably a silver braided hose with a tap on it connected to the mains. You need to find the filling instructions. If you haven't got any, raise a new post with the make and model of the boiler in the heading.

 

[loumc]

OK, great, thanks for all your help!!