Hot Water only when Central Heating is on Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[Roger9786]

I have just bought a house which has a Baxi Combi boiler and a hot water tank (not sure what this is for). I have noticed that if the Central Heating system is switched on, then I get warm water through the taps. When the central heating system is switched off, even though the Hot water light on the control panel is on, I don't get any hot water. Does any one have any ideas what could be wrong or waht I should get checked ?

Thanks in advance for your help.

[marrtin]

It seems possible the boiler is not a combi but a condensing system boiler which heats water in the same way as a traditional system. ie, the boiler needs to be on for a while to heat the water in the tank. Could this be correct?

[Roger9786]

Hi,
thanks for the reply. Sorry how do I find out if the boiler is a condensor boiler and not combi ? Will it say somewhere on the Boiler?

[marrtin]

Sorry, maybe I didn't explain properly.

A condensing boiler is just a name for a highly efficient style of combustion arrangement where almost all the heat is removed from the exhaust gases. So much so that water condenses in the combustion chamber and flue and has to be removed by a dedicated drain assembly. To comply with new energy efficiency regulations, all new boilers must be of the condensing type.

Combination boilers are designed to heat the incoming mains water instantly as well as supply heated water to the radiators. So as soon as hot water called for, the boiler fires up to satisfy the demand.

System boilers are linked to a heating circuit in a traditional way. Hot water produced by the boiler is pumped through a heat exchanger in a storage tank which produces a store of hot water over a period of time. When hot water is called for, water is drawn from the tank store, not from the boiler.