Radiator only warm when hot water is being heated.

[forgotusername]

DAK why this curious situation is happening. The boiler is gas fired and can be timed to heat radiators and/or hot water. The hot water is held in a tank adjacent to the boiler. The radiator in a bedroom on the same floor is stone cold when the boiler is on the CH program but becomes hot when the water in the HW cylinder is being re-heated. Some of the pipework, including this radiator was recently altered by a plumber in order to fit a new radiator.

[staffordian]

Looks like a plumber's cock up.

Sounds to this layman that the new rad has simply been added to the hot water circuit rather than the heating circuit, so as soon as the system calls for hot water, the hot water tank and this new rad get hot, and when heating only is selected, the diverter valve shuts off the flow to the tank, and to the new rad.

[forgotusername]

That is a plausible explanation. I'm unfamiliar with the layout of pipework but will pass that on to the homeowner concerned. As the work was only done a couple of months ago, he may be able to get the plumber back to correct it. Thx.

[DrFfybes]

A Stafforedian says - it is plumbed into the wrong circuit.

One of ours is the same, but as it is in the airing cupboard we assume it was designed this way.