Cold bathroom

[JBR]

We have a towel rail in our en-suite bathroom which was added to the existing central heating system soon after we moved in some years ago.

Unfortunately, it never gets really hot compared to the other radiators. I understand that towel radiators are not designed to heat a room, but I still think it ought to be hotter than it is, especially as I removed the TRV that it came with and ensured every other radiator has a TRV fitted.

I don't know whether this would have any bearing on the problem, but we live in a bungalow and the en-suite bathroom is a couple of steps lower down than the rest of the house.

My first wife wants the towel rail replaced by a conventional radiator, but I'm not sure that would make much difference if the towel rail never gets hot anyway.

Any ideas, please, of how to overcome the problem?

 

[jeff the gasman]

Make sure that both valves are open and the pin on the TRV is moving in and out. Turn other radiators off and it should spring into life.
Fitting a radiator would not improve anything until the circulation issue is solved
Jeff

 

[JBR]

Many thanks for your advice.

Although there is now no TRV on the towel rail, I did check earlier that the pin on which the TRV would sit moves in when depressed.

I haven't yet tried turning off all the other radiators, but will do this and see what happens.

Assuming that the towel rail heats up sufficiently, is it then just a matter of 'balancing' all the other radiators? I've heard that this is done by partially closing the 'other' valve (not the TRV) on each radiator, but of course I have never done it before so I don't know what I'm doing. I assume that just turning down the TRVs on the other radiators won't balance the system.

Perhaps I should just call in a plumber or central heating engineer, but I'd like to have a go myself first, assuming that I can't to any real damage by doing this!

 

[bolshy]

Details on balancing your rads can be found in the FAQs on this forum.

 

[JBR]

Details on balancing your rads can be found in the FAQs on this forum.

Thanks. I'll have a go. It can take quite a time to do it properly, though, so I've heard!

 

[JohnD]

since this was an addition, it's possible that it was added onto the pipes for another nearby radiator, and the original one may be taking most of the flow. If this seems likely, start by turning off the radiator that is probably the source.

Are the radiator pipes 15mm, or are they little ones, the size of a pencil?

If the rail doesn't heat up even when you turn all the others off, there may be a partial blockage. With it being lower, there's possibly sediment in the pipes. Have you got a boiler with a pressure gauge, or is there a feed and expansion tank in the loft?

Have you got a hot water cylinder close to this bathroom?

 

[JBR]

since this was an addition, it's possible that it was added onto the pipes for another nearby radiator, and the original one may be taking most of the flow. If this seems likely, start by turning off the radiator that is probably the source.

This is quite possible. I can try that when I do the first part of the balancing.

Are the radiator pipes 15mm, or are they little ones, the size of a pencil?

They look like 15mm

If the rail doesn't heat up even when you turn all the others off, there may be a partial blockage. With it being lower, there's possibly sediment in the pipes.

Yes, that crossed my mind too. Is there an easy way to find out?

Have you got a boiler with a pressure gauge, or is there a feed and expansion tank in the loft?
Have you got a hot water cylinder close to this bathroom?

It's a combi boiler, with a pressure gauge, direct from the mains. No feed or expansion tank and no hot water tank.

Thanks, I appreciate your help.

 

[JohnD]

If the rail doesn't heat up even when you turn all the others off, there may be a partial blockage. With it being lower, there's possibly sediment in the pipes.

Yes, that crossed my mind too. Is there an easy way to find out?

Turn off the radiator valves at both ends, tightly. Open the rad bleed valve to verify that water does not squirt out. Undo the rad valves from the rail. lift away the rail (dirty water will run out). Hold a basin or bucket under one valve, and open it. Water should gush out. Then try the other. You may need someone to top up pressure with the filling loop. If there is soft sediment, it may come out into your bucket (it will stain carpets).

 

[JBR]

If the rail doesn't heat up even when you turn all the others off, there may be a partial blockage. With it being lower, there's possibly sediment in the pipes.

Yes, that crossed my mind too. Is there an easy way to find out?

Turn off the radiator valves at both ends, tightly. Open the rad bleed valve to verify that water does not squirt out. Undo the rad valves from the rail. lift away the rail (dirty water will run out). Hold a basin or bucket under one valve, and open it. Water should gush out. Then try the other. You may need someone to top up pressure with the filling loop. If there is soft sediment, it may come out into your bucket (it will stain carpets).

Thanks again John. I'll add that to my list.

 

[JBR]

I have now balanced the first three radiators in the 'heating up order' and, already, I now find that the bathroom towel rail (the last in the order) heats up nicely. My first wife is over the moon and I am grateful to find that the circuit doesn't seem to have any obstructions in it.

I only did the first three yesterday because I found the temperature readings were varying a little and I wanted to be as precise as possible, so consequently I was taking rather a long time over it. Also, the place was becoming like a bloody oven, what with the heating being on full blast!

I'll do the other eight tomorrow... maybe.

 

[JBR]

I don't know whether anyone is still listening, but here goes.

I had a go at balancing the remaining eight radiators today, but had some problems. A couple of radiators seemed to be at roughly the same temperature at each feed pipe even when the valve was almost turned off. Obviously, when I closed the valve the radiators cooled down, but I seem unable to achieve a situation where there is an 11 or 12 degree difference.

So I gave up! Perhaps my multimeter isn't working properly, although other radiators could be balanced pretty accurately.

Anyway, I decided to do what the professionals do and just feel them! As long as they are all roughly the same temperature (as far as I can tell) I suppose that's as good as I'm going to get.

The important thing is, I think, that they all now warm up, including the bathroom towel rail which was the one my first wife was complaining about!

 

[JohnD]

balancing is done with the lockshields almost completely closed. It takes only a fraction of a turn to make a noticeable difference in flow.

If you fully close them, then open half a turn, or maybe a turn, you can then tinker in quarter-turns or less for fine tuning.

If you have TRVs, that will in time close down the excessively hot rooms, but it is still best to balance as accurately as you can, otherwise some of the rads will stay cold until all the other rooms are hot.

After you have balanced all of them once, you will probably have to go round and tinker again. Give them time for the temperatures to stabilise after each change.

 

[JBR]

More invaluable advice. Thank you. Yes, I'll go around them again when I've time.

Yes, I'd noticed that the valves must be almost closed to start with. I'm sure that was the initial problem: all the radiators had their valves almost or fully open before I started, so the first two or three were getting all the hot water and the other poor things further down the line didn't get a look in. Like other things I've discovered about this house over the years, the previous occupant was called Roger the Bodger.

The 'problem radiators' were almost closed (less than a quarter turn) before I could get them about right, but the temperatures were still nowhere near 12 degrees in difference. Is it possible that, once the radiator is hot, the feed pipes could become hot by conduction through the metal from the rest of the radiator, and that this could skew the readings?

 

[JohnD]

nope

Are the rads fully hot, top and bottom, sides and middle?

Could someone have altered the pump speed?

 

[JBR]

Yes and no!

Yes, the radiators are hot all over. As far as I'm aware, no the pump speed hasn't been altered. We have the boiler serviced every year, but there has been no mention of the pump speed being altered.