I am a new house owner and are having issues with the central heating and hot water. As of sunday, it went offline without warning. The gas flame in the boiler is fine, but the tank in the airing cupboard is cold, I believe it is a combi boiler? The panel in the bathroom states the heating and/or hot water go on-but they haven't. It's also started humming softly, when the panel is on but there is no sign of the water heating.

If we put the immersion on we get a limited amount of hot water, so the tank does heat up-it just won't run without it. Could you please advise as to what kind of problem this is? We have no idea whether this should be on/off-we know the boiler works-heats up-so it doesn't need replacing but we are unsure what's going on.

We have a plumber coming to look at it, but any ideas/advice would be much appreciated. Thanks

Ann, May 2008

cos you have no heating or hot water, i would go for pump too.

ps you have a system boiler rather than a combi

iain, May 2008

No, no heating, not hot water-everything is cold, the water won't even go lukewarm. I'm not sure about the buzz-its only started since the water/heating went offline, before then it was fine noise-wise.

I'll pass this along to my friend, he's a lot more savvy but the pump seems a good thing to look into. Thanks guys.

Ann, May 2008

A combi boiler produces hot water on demand, both for central heating (CH) and domestic hot water (DHW). If you have a copper cylinder, then this stores hot water produced by an 'ordinary' boiler. An immersion heater will heat up the top third of this cylinder, but not much more. The hum you hear could be the pump running, or simply a buzz from an electric circuit board. Do you have hot radiators?

John, May 2008

It sounds as though the pump might be jammed. If you know where it is then there should be a large screw head in the centre. If the c. heating/water is switched on , undo this large screw and inside should be a slotted spindle spinning round. If it`s not spinning then try + turn it with a screwdriver ( or tap the pump casing)..This is a common fault , but not necessarily what`s wrong with your system. It`s safe to do what I`ve suggested but if in any doubt, then leave it for the plumber. (note : New pumps cost around £50 plus 1 hour fitting time)

Jeff, May 2008