Removing a radiator

ronnyb_2

I am removing a radiator in order to decorate. When replacing it and refilling it how much water should be put back into the system via the filling loop (it's a combi boiler). Does the boiler need to be on or will the water pressure alone fill it.

ariba10

Make sure the boiler is off.

You need to get one to one and a half Bar on the gauge on the boiler, and check it again after the boiler has been running for a while.

Avoriaz

If possible, recover the drained water and reuse that to refill. This will reduce the slight dilution of any protective additives.

You can do this easily is you have an unpressurised system with a header tank. Turn off the supply tap to the header tank. Drain the radiator and save the water. Fit the new radiator and add the saved water to the tank as the new radiator fills and then turn the supply tap back on.

It is probably harder or maybe impossible if the system is pressurised. I don’t know much about them.

It isn’t very important so don’t worry if you can’t do it.

ronnyb_2

Thanks all.

Hizz

Whilst you've got the radiator off, it's worth taking it outside and putting a hose pipe in to 'swill' any sedament out. This maximises performance within your heating system.

I personally would never save and return any water drained from a radiator. Never heard of this before and don't see any benefit to putting the 'black stuff' back in.

derrick

ariba10 wrote:

Make sure the boiler is off.

You need to get one to one and a half Bar on the gauge on the boiler, and check it again after the boiler has been running for a while.

Should be about 0.8 bar when cold, this should increase to around 1.2-1.5 bar when hot depending on system volume.

ronnyb_2

Its a new system but I intend to remove every radiator as the whole house needs decorating, we,ve only just bought it. Avoriaz is right when he says about diluting the additives ie the corrosion inhibitor, particularly when every radiator is to be removed. Another idea I've had is to loosen the valve on the side of the radiator and lay it on the floor to avoid any water loss. Otherwise how do you top up the inhibitor?

Avoriaz

Hizz wrote:

…..I personally would never save and return any water drained from a radiator. Never heard of this before and don't see any benefit to putting the 'black stuff' back in.

It is not a very important point but it can slightly reduce the amount of corrosion. Fresh water will have certain dissolved minerals, acids etc that corrode a c/h system. Water that has already been inside the c/h system for some time will have already “used up” it’s corrosion potential whereas introducing fresh water introduces new contaminants. There is also the affect of dilution of any anti corrosion additives.

It is far more important to add corrosion inhibitors to the water than to recycle the used water.

I should have also said that you should not reintroduce any sludge etc that is removed from the radiator.

Avoriaz

ronnyb wrote:

… Another idea I've had is to loosen the valve on the side of the radiator and lay it on the floor to avoid any water loss. …..Otherwise how do you top up the inhibitor?

I think you will find it very difficult to remove the radiator without fully draining it. Once you loosen the valves the water will start to pour out and I doubt if you can win the race of getting the radiator on the floor before all the water comes out all over the floor.

You top up the inhibitor via the header tank in an unpressurised system. There will probably be instructions with the inhibitor but this is how I have done it. Turn off the supply tap. Empty the header tank with a plastic jug or by draining via a radiator or other drain point. Pour sufficient inhibitor in the tank, preferably directly down the pipe that feeds the c/h system. Then top up the tank a little with either recycled water or fresh water and repeat the drainage until most of the inhibitor has gone into the c/h system. Then turn the supply tap back on. If you just add the inhibitor to the tank, you risk it just staying up there or sitting in the feed pipe and not getting added to the circulating water in the radiators. Common sense should tell you how much water to drain off to ensure good mixing.

I don’t know anything about pressurised systems so I can’t advise there.

ronnyb_2

Thanks but it's a combi boiler and pressurised system, there's no header tank. I've removed radiators before with a conventional system which fills itself up when you bleed the radiator. This is obviously more tricky.

angeleyes

you should have two washers ,one on each side, put a towel under each (with someone else helping) each have a spanner to fit the washer and loosen them enough to drop the rad down then quickly retighten so the rad is resting on the floor - when finished decorating do the same to put it back up ... this is how we redecorate easyier than draining and taking off completly