Draining the central heating system
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Draining the central heating system

by yrrab » Thu Apr 16, 2009 11:14 am

I used to have a combination boiler and this was replaced a couple of years ago with a condenser boiler. I want to replace a radiator in the bathroom with a towel rail. I was just about to remove the radiator when I thought I had better check with diydoctor. Instructions on draining the central heating system refer to an open system only. It says for sealed systems I should get a plumber to do it. Is my system a sealed system? Does this mean I shouldn't fit the towel rail myself? There is no hot water tank in my system. The water is heated through the boiler.

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by Steve the gas » Fri Apr 17, 2009 5:57 am

From what you are saying you still have a combi.It's just a condensing combi, - make/model?
Does it have a pressure guage and filling loop?

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by rosebery » Fri Apr 17, 2009 8:29 am

If you have no tank you still have a combi - albeit a condensing one.

Of course you can do this yourself.

Switch off power to boiler.

Ensure filling arrangement is not connected.

Drain water from system via drain cock at lowest point of system.

Change rad for towel rail.

Refill system.

Switch power back on.


Don't forget to replace the inhibitor.


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