Heated towel rail - help!

[chesirecat99]

More of an AIBS (am I being stupid) rather than an AIBU...

My bathroom has a heated towel rail. It was brand new when we moved in but there was no manual, there is no obvious branding apart from a label with an X logo to try and find a manual, and it has never really worked. It gets just barely perceptibly warm in places. The top gets warmest, then the bottom and the middle is the coldest part.

I've tried bleeding it. There was no air.

It has 2 valves at the bottom. The pipe coming up to the valve on the right is hot, as is the valve itself, but the valves don't seem to do anything. They just seem to be screw on caps IYSWIM? If you turn them, they just screw off. I am guessing I need to attack what is underneath with a spanner or allen key to adjust the valve?

I'm also guessing that the cold middle panel is some kind of blockage/air lock?

AIBU to ask someone to save me from a winter of wet towels? Maybe the hero, @PigletJohn?

photos please

incl pipes and valves

do you think it was added after the rest of the heating system was fitted?

have you got a hot water cylinder nearby?

What radiators are close to it?

You are a star, PigletJohn!

It was added after the rest of the heating to replace the bathroom radiator, although the boiler was replaced at the same time.

There is no hot water cylinder. The nearest radiators are in the hallway and my bedroom.

I'll get some photos when I am home but the pipes just come straight out of the wall next to each other, straight into the valve. They look like normal heated towel rail valves, like this:

www.plumbworld.co.uk/duratherm-angled-radiator-valve-pair-3983-1254208

The silver cap bit just screws on and off though, it doesn't appear to do anything, it's hollow, and empty like a wine bottle screw top. Underneath is a brass hexagonal nut thing.

Turn off ALL the hot ones. Does the cold one now heat up?

Most of the radiators don't have thermostatic valves and I am a bit loathe to fiddle with the valves as last time I did that 2 of them broke. They are ancient.

I've tried turning up the heating up to 24C. It gets warmish when the other radiators are almost untouchably hot. Warm enough to be discernible when you touch it but not warm enough to heat the towels or the room.

I have photos now.

Please pretend you can't see the dust!

i think the radiators need balancung.

When they broke, was it the plastic knob that cracked? Or something else?

Something internal, I think. Two of the radiators were off and couldn't be turned on, we had to replace the valves. So the may actually have been broken by the workmen who did the renovations rather than me trying to turn it on.

So, even if the problem isn't the radiator valves on the towel rail, how do they work?

I think that the hot water being pumped round is passing through the other radiators, and not through the towel rail.

imagine two rivers connected by numerous streams. If enough is passing through the first ten, there may be insufficient flow to go through the eleventh.

If this is the case, closing all the hot rads will force the water to go through the rail. You can try closing whichever rads have a valve in good condition and this may send some flow through it.

If you end up needing new valves, get Thermostatic Radiator Valves.

I am particularly fond of the Danfoss RAS-C²

Ok. Although the radiators in the rooms after the bathroom are fine. It's definitely time to sort the radiators without thermostatic valves out. There are a thousand little things that need doing that got forgotten about once COVID hit. Half of them new things that were bodged by the renovators... I guess I will have to get a plumber in to sort that and the towel rail out.

Thanks, @PigletJohn. You are a MN legend! I wish I could find a real life reliable plumber.

if you had new valves fitted, turn those off first. They might not have been balanced.

LTB