How to drain down Worcester Bosch combi but keep DHW

[cwood]

Bathroom renovation means I'm moving the pipework of an existing radiator to accommodate a towel radiator. I know you'd normally just drain down the CH system, do the work and then refill. However, once I've moved the pipes and fitted the new valves, tested the connections with a re-fill and reinstated the plasterboard wall over it all, I'll need to do a whole load of tiling over that area before finally hanging the towel rad.

So here's the question: I've got a Worcester Bosch combi, which I know has an integral bypass in it, and I don't want to have to rush at the tiling just because there's no hot water in the taps, so what do I do to drain down the CH but maintain the DHW?

Thanks in advance for your help folks.

 

[ianniann]

I suspect the advice you get here is going to be a big fat "don't do it!". Which combi is it exactly?

You could temporarily rig up a fixed bypass relatively close to the boiler and cutting out your new pipe works, so that a very small central heating circuit can be kept full of water Obviously you wouldn't want to be demanding heat from the boiler like that but it would allow the boiler to remain on and supply hot water.

 

[cwood]

It's a Worcester Bosch Greenstar 25Si. The point of my post was that I thought these combis were capable of running the DHW even with the CH drained down because of the integral bypass. Otherwise I definitely won't mess with it!

 

[clf-gas]

Drain down and adjust pipework as required and then cap off with pushfit stop ends. Refill system and carry on at leisure. when ready to hang rad drain down again.

It wont hurt to put in some system cleaner after first drain off and run heating for a while now and again.