PCPaul wrote:

Is this one advantage of a combi? We've had the CH side of it switched
off for months but at least the rest of it has been going strong.

OTOH presumably if the 3 way valve I assume it has inside sticks it isn't
going to be a local plumbers merchant job to fit my own spare...

Is this one advantage of a conventional system? We've had the CH side
of it switched off for months but at least the rest of it has been going
strong.

Presumably if the 3 way valve in the airing cupboard sticks it's going
to be a local plumbers merchant job to fit my own spare...

:P

Andy