Coombi boiler flow stopcock Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[dpicton]

I wish to drain down the radiator system heated by a combi boiler. I don't see any stop valves next to or near the boiler - should there be one. Would the stop valve on the incoming cold main be the valve to operate before draining the system?

[rosebery]

Yes.

Cheers

[htg engineer]

You can drain the CH system without isolating any valves, as to refill you would have to use the combi fill.

Closing the MCWS isolation valve will stop the hot water - nothing else.


htg

[rosebery]

"Closing the MCWS isolation valve will stop the hot water - nothing else."

It will stop the CH system filling if someone leaves the combi fill valve open at the wrong time though!

Cheers

[htg engineer]

But the cmbi fill should not be connected unless re-pressurising - it's against water regs to leave combi fill connected permanently.


htg

[rosebery]

Yes I know that but how many people do? My suggestion of isolating at the stopcock is belt and braces for those that do.

Cheers