I have a heated towel rail in the bathroom, its at best only warm to the touch even though all the other rads are boiling. I've tried bleeding it but water came straight out so no trapped air.

It is above the end of the bath so slightly higher than all the other upstairs rads but surely this shouldnt make a difference? Cant think why its not getting hot – suggestions please?

It's probably not hot due to it's low temperature.

Sure you got all the air out ?
Might be furled up ?
Actually I have no idea..

It's not turned on?
Seriously… is the valve fully open?

sounds like it needs bleeding – trapped air could be the problem.

is it hot at the bottom? if so then its almost definately tarpped air, as the water wont be ble to rise all the way up the radiator.

are both radiator taps fully unwound? do them with a pair of pliers to be sure. Also try thumping it whilst bleeding (make the air bubbles rise to the top)

if that doesn't solve things, turn both off, drain the radiator, then blast some water through it, could be blocked up with gunge of some kind

Its definitely turned on.
I have bled it but no air came out, only water (clear water, not full of crap).
Its the same temp all the way up so almost certainly not trapped air.

Maybe the guy who sold you the house lied about the heated nature of the towel holder?
😉

got any valves on it?

Does it have TRVs? If so unscrew the top and press the pin down – sometimes they stick.

Is the pipe hot that feeds it? I had a similar problem with a radiator and the return pipe was blocked as it was on its own little 'circuit'.

Its got shut off valves but not TRV's.

Need balancing?

how's it connected to the heating? I've seen some towel rail heaters that are connected into the tank-heating loop. They only get hot when the hot water tank is heated. Very odd.

Do the supply pipes pass through a very cold place before reaching the bathroom? Or, are heat sucking monsters from another dimension abstracting your energy before unleashing a terrible assault on the minds of men?

Are its supply pipes furred up? You want good flow to radiators. What happens if you turn off all but one of your other radiators?

If it is clear water then you need some inhibitor in your system, but hat isn't causing this problem*.

*It will cause other problems later on though…

It's apparently very common for towel rails to be connected only via gravity feed to the tank, certainly if you have something like a log burner too IIRC – my brothers system uses the towel heater as a "burn off" radiator if the rest of the central heating isn't required and the log burner is churning away.

Defo balancing or kinked/blocked/badly installed feed pipes.

Is one of your other radiators really hot (ie, hotter than the others)

wind in the balancing valve a little on that one, and see what happens to the rest.

Its definitely turned on.
I have bled it but no air came out, only water (clear water, not full of crap).

Been having problems at home with my central heating, sticking 3 way valve, British Gas chap came out to change the valve and told me that my system was gummed up with sludge and for the princely sum of £600 it could be cleaned. The water from the rad drain/bleed points very clean.

Not that he suggested anything but I have bought ‘fernox’ poured it in the tank in the attic and let it run around the system for a few weeks, the water that first came out was brown/black with lots of grit in it, I have flushed the system a few times and still the water is brown but getting clearer. Plan some inhibitor for the New Year after a few more flushes

Three of the radiators that never really got piping hot are as hot as the others.

Hope this helps

I've seen some towel rail heaters that are connected into the tank-heating loop. They only get hot when the hot water tank is heated. Very odd.

Fairly normal, it means the readiators still warm the towels in the summer when the heating is turned off, We also have a radiator connected in the same way in the airing cupboard for the same porpoise.

As to the present dilemma, no idea

what colour should the water be? Mine is normally black, not sure if that's a sign of inhibiter, or it's f*cked 😀

Fairly normal, it means the readiators still warm the towels in the summer when the heating is turned off, We also have a radiator connected in the same way in the airing cupboard for the same porpoise

That makes sense. It's familiar in older installations or when you have the hot water tank near the bathroom. Seems odd these days with local control valves on most radiators. Bathroom radiator is usually left without one of these thermostatic valves if its part of the main heating circuit.

have bought ‘fernox’ poured it in the tank in the attic and let it run around the system for a few weeks, the water that first came out was brown/black with lots of grit in it

Isn't the tank in the attic the water supply tank for hot water in old 'open' gravity feed systems? Seems weird that there'd be a gravity feed tank for the radiators.

Most likely balancing, one of the most common things that I seem to have to put right on many systems. It is part of commissioning and should be carried out, but because it can take quite a while people don't bother. And one of the reasons they don't bother is that it costs money to do it, and it is a competitive industry, and therefore all the customer ever bothers with is how much, not how good. A big system can take over half a day, which is in anything from £100 upwards on the estimate, so it rarely gets done. (sorry for that bit but get fed up with it sometimes).

Mail me you address and I'll give you a quick lesson on balancing, be away from PC till tomorrow though.