Draining down combi, but use hot water

[marsaday]

Can i drain down my vaillant combi and still use the hot water.

i want to change 2 rads this weekend, but also would like to use the hot water.

Can i do this or by draining down do i stop the hot water production as well?

 

[Gr fto reborn]

You can't leave the heating circuit with out pressure the boiler will not fire. There is a way it can be done but it must involve creating a small loop between the flow an return on the boiler and then charging that loop up. The boiler will then be able to heat the exchanger to heat the water.

Note I have never done this before but have known of people temp running a combi as a water heater. This is how I assume they have done it. Am I right guys?

 

[Billy Bob Bob]

you could cap the plumbing if its only 2 rads,ie the ones your working on re-pressurise and fill the system back up if you want to use dhw

 

[marsaday]

thanks, but we will just have a cold wash for one night. would be nice if it was easy to do, but not that big a deal.

 

[moony]

yeah can be done - i have installed combi's in houses with no rads and just put a loop in the flow and return - that way the owner can have rads added at a later day

 

[Robtheplumb]

Changing 2 radiators isn't going to take long, what else do you have to do??
TBH you don't need to drain down if doing a like for like swopsies

 

[Gr fto reborn]

You could shut the rads off de pressurise the rads from the bleed use a wet vac and snatch them from the system but your trv may let by. Take the trv heads off depressurise the rads and if the pressure gauge on the boiler hasn't moved should be good to snatch the rad off. If your not 100% you willbe better of draining down properly or you may end up making a mess.