I recently turned the water off to repair a pipe which I had accedently hammered a nail through.
When I turned the water back on everything worked fine, but I've now noticed that when I put the heating on, the radiators all work but the water in the hot water tank doesn't heat up. Water comes out of the hot tap as normal, but it is just cold.
Any idea what could be causing this?

Cheers,

Rob

I recently turned the water off to repair a pipe which I had accedently hammered a nail through.
When I turned the water back on everything worked fine, but I've now noticed that when I put the heating on, the radiators all work but the water in the hot water tank doesn't heat up. Water comes out of the hot tap as normal, but it is just cold.
Any idea what could be causing this?

Cheers,

Rob
If you drained the system down to make the repair, then you probably need to bleed the air out of the radiators -- There should be a bleed valve located somewhere on the side, near the top of the radiators.

Ok, I'm a bit confused. Your hot water heater is also your heat? I've seen a few of these units but they are rare, unless it is a modern combo-boiler.