Radiator fails to heat up

[BazzerLondon]

Hello

My house has an old but conventional (as it was then) gas central heating system.

It has a pumped supply to the radiators but the primary hot water supply to the hot tank is gravity fed and also feeds the bathroom radiator.

All is working well except for the bathroom radiator which gets only moderately warm at the top but gets progressively colder towards the bottom. The hot water tank contains hot water from top to base and its base and the radiator base are on the same level.

I've tried a number of things to identify the problem - valve seems to be working ok - bleeding the radiator to no avail.

Any ideas would be appreciated.

 

[Chuck]

Assuming the towel rail is the 'always on' or 'bypass' emitter, sludge has probably accummulated in the loop of pipework connecting the towel rail to the cylinder. Needs flushing or, preferably, upgrading to a pumped system.

 

[BazzerLondon]

Chuck. Thanks for your response. Very much what I expected. One thing that I would like to have tried would be to close both radiator valves, remove the radiator and flush it out. However, in the wisdom of the installers, there is only one valve, so a much trickier operation and one for the professionals I think rather than for me (an expeienced DIYer)!!!

 

[Chuck]

one for the professionals I think rather than for me (an expeienced DIYer)!!!

That's probably the right call. Just cleaning out the radiator is not much good unless you can also flush out the gravity circulation loop. This is not beyond the ability of a DIYer but without the right gear and some hard-one experience it's likely to be messy time-consuming and not entirely successful.

Even if you were entirely successful, in a year or two it'll need doing again unless you convert it to fully pumped circulation.