I'm planning on replacing all the old radiators in my house. I have a combi boiler and was wondering, as it might take a couple of days, is it OK to drain the central heating system but leave the boiler on so we can have hot water? Obviously I'd turn the boiler to 'water only'.
Is it OK to have hot water with a drained sealed system?
- Thread starter Pineman
- Start date
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you could but it's not advisable
1 after hot water demand the boiler dumps residual heat into the heating system
if it has nowhere to go the boiler will overheat
2 if you close the isolater valves under the boiler they will probably start to leak
1 after hot water demand the boiler dumps residual heat into the heating system
if it has nowhere to go the boiler will overheat
2 if you close the isolater valves under the boiler they will probably start to leak
It all depends on which boiler you have.
I would say that with virtually ALL boilers you can pressurise it and use it for hot water only while you change your rads.
In spite of what the others say I do it regularly and have never had any problems.
I have seen several Biasis and a Performa used as a hot water unit with no rads connected. On one the installer had connected a pipe between the flow and return, the others were capped off. BUT these boilers have a built in bypass.
If your boiler has a built in bypass then I would say just do it.
If you are not sure, or it has not, then temporarily looping the flow and return together.
Tony
I would say that with virtually ALL boilers you can pressurise it and use it for hot water only while you change your rads.
In spite of what the others say I do it regularly and have never had any problems.
I have seen several Biasis and a Performa used as a hot water unit with no rads connected. On one the installer had connected a pipe between the flow and return, the others were capped off. BUT these boilers have a built in bypass.
If your boiler has a built in bypass then I would say just do it.
If you are not sure, or it has not, then temporarily looping the flow and return together.
Tony
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agile said:
can't see what difference a built in bypass will make at best 150mm of 8mm tube
ok you have just ran the hot water
the main h ex is hot
the dhw h ex is hot
where is the latent heat going
the main h ex is hot
the dhw h ex is hot
where is the latent heat going
no auto bypass then
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