Radiator either red hot. Is thermostat broken?

[AliceA]

Hi

We have recently had a baby and we are now using the 2nd bedroom, but can't seem to get the temperature right in there. We've noticed that the radiator is always red hot when turned on, regardless of what setting the radiator thermostat is set to.

All radiators in the house have thermostats attached, except the one in the room where the thermostat is, and all seem to be working well except this on.

I have no idea if this radiator is the last on the system. The entire system, boiler and radiators have been in for approximate 18 months.

Could it be that the individual thermostat needs replacing/ fixing?

Any help would be appreciated as our little girl woke up cold this morning, as we fear if we have the heating on she will overheat.[/b]

 

[Burnerman]

It certainly seems that the radiator TRV (Thermostatic Radiator Valve) is in the huff - usually they fail in the off position!
As the valve head senses heat build up it depresses a pin in the lower part of the valve restricting the water flow through the radiator.
Does the valve head feel loose at all or is it so positioned that its getting a draught so it can't sense the room temperature?
John

 

[JohnD]

You say you have got a room thermostat fixed to the wall in your house. Which room is it in?

You can balance the radiators using the lockshield valve so that the radiator in baby's room heats up no faster than the rad in the room with the wall stat. This should always be done but some people don't bother as TRVs will hide the problem.

You can remove the thermostatic head from the valve and swap it for the head of another valve. Knowing the make and model of the valve you can then buy a new one. Changing the head needs no plumbing and no water comes out. If the valve under the head is faulty, that will be a simple plumbing job.

Wind the head up to its highest position before trying to remove or replace.

 

[AliceA]

Thank you for your help, much appreciated.

The head doesn't feel loose, forgive me, but I assume the head is the white plastic bit? The thermostat is a pegler bulldog?

There is a metal ring below it, which can be tightened, which I have now done. Is this the lock shield valve?

The thermostat is in the lounge. How do you balance the two?

Great news that it can be replaced without having to drain the system!

 

[Terry7556]

the peglar is the trv, the other end is the lockshield. in the lounge you should have two lockshields on the rad. if you had a trv on that one, the trv and the thermostat would always compete against each other.
look on the FAQs at the top of the posting list page , and find the entry on balancing rads
boiler and central heating FAQS

 

[JohnD]

you can take the plastic thermostatic head off by undoing the metal ring you describe. It may undo downwards, you need to identify the make and model of your valve to be sure.

Post a photo or look at some of the pictures on
http://www.screwfix.com/c/heating-plumbing/trvs/cat831012

 

[AliceA]

Thank you.

After swapping the thermostat with another in the house, we still seem to be experiencing the same problem when using a different thermostat.

Though the rest of the house was a toasty 19 degrees, the nursery was like a sauna!

The radiator is positioned on an outside wall, but is not caught in any draughts.

Could there be a problem with the radiator itself?

 

[Burnerman]

The radiator is fine, and so is the water flow through it....many people would be thrilled at this one
As the TRV head seems to be OK, then its the valve below the head thats sticking open.
With the head off, did you see a round pin about 2mm in diameter poking up? The TRV head is meant to push the pin down to close off the water flow.
John

 

[ianmcd]

hi Alice you do realise that is you have one radiator with the valve set at say setting 2 and another set at say setting 5 and both were calling for heat then both radiators would be at the same temperature, the valve senses the temperature of the room not the radiator, it doesnt mean that the radiator set at 2 will be cooler than the one set at 5

 

[Charnwood]

I wondered how long it would be before someone mentioned that.
It took 6 posts. It's the first thing that struck me about the OP.

 

[HDRW]

Alice,

The clincher would be to turn the Thermostatic Radiator Valve (TRV) all the way down to its lowest setting (1, or 0, or *, whatever) and then wait to see if the radiator cools down. You'd have to make sure the system was providing heat, perhaps by turning up the main wall-thermostat to make sure it stays on.

If the radiator stays hot like this, the valve part of the TRV must be stuck open, so either needs to be freed (with the top section removed, pushing the pin to see if it will move down, and gentle tapping to free it if not) or it needs to be replaced, which involves draining the heating system below the level of the valve and then replacing the whole valve with a new one, then refilling the system and bleeding this radiator (at least - could need some others, or even all of them bleeding).

Good luck, and please let us know the result!

Cheers, Howard

 

[AliceA]

Hi

I am now away for a few days but will try all of the suggestions when I return and let you know how I get on. Thank you.

The valve does seem to be controlling the flow, as I have tried turning the heating on whilst the radiator is turned off and then turning to 5. Other radiators in the house heated up as normal. You can then feel and hear the heat and water flowing through. Would this happen if the pin was working correctly?

I understand what you mean re different settings in different rooms, however, the nursery radiator continues to stay hot even when the room has reached and exceeded what the room thermostat has been set to. When the heating is switched on, no matter what temperature is specified, the radiator goes straight to hot and then doesn't adjust when the room has reached the preferred temperature. So we can either have it hot, or have to turned it off.

 

[ianmcd]

The room thermostat has no control whatsoever over what you set the TRV in the nursery to the room thermostat senses the temperature of the room that it is located in only and the TRV in the nursery senses the temperature of the nursey room only , they do not communicate with each other in any way