We may be in a position where we want a new combi commisioned to supply hot water some time before we are anywhere near installing the replacement pipe runs etc. for the central heating.
Now AIUI we will need water in the CH side at about 1bar pressure otherwise the boiler won't run. We don't intend to use the heating circuit, so what is the safe minimum to allow the boiler to run? Short loop of 22mm? Single temporary radiator to give some volume so pressure doesn't fluctuate too much?
Cheers
Dave R