I have a Vaillant Turbo Max Combi Boiler and a sealed heating system. I want to add a radiator and renew a couple of others which are not very efficient any more. For this I need to drain the heating system to work on the plumbing of additional radiator and exchange of others. But in the meantime I need the combi to continue to supply hot water. Will my boiler continue to work?
Noni.

Noni Mistry, August 2008

yes, if you first shut off the central heating flow and return valves under the boiler first, but make sure the boiler cant run in heating mode. ie turn roomstat down and turn timer off etc.

tojo, August 2008

no , the boiler needs pressure to operate correctly

kieran, August 2008