Another central heating question

[rlw]

My guess is that the answer is "don't do it" but I'm not sure.

We have a leaking c/h pipe under the concrete floor in the sitting room. The "dig team" are coming tomorrow. The leak is on the inward side of the radiator. The heating is switched off to stop more water being pumped out, rather than trickling out (I hope).

Question. We have a damn great hot water tank in the loft and one radiator on the hot water circuit and it would be nice to have a warm bathroom and a hot shower in the morning. But....will using this cause more water to be pumped out under the floor or is there some miraculous, only understood by plumbers, system by which the c/h pump is not used?

If not, its the immersion heater and a bloody cold bathroom.

Thanks

[robinhood21]

Turn the boiler to hot water only and it should be OK.

[rick.e]

Remember that if you have (or had) a sealed system, then now the expansion will be accomodated by squirting water out through your leak, and when it cools, the contraction will suck air in. Also, if you already have air in (very likely) then expansion will be greater.

[jonnye]

sounds like it probably a gravity system ,if it not leaking too badly turning the heating on shouldnt make much difference