Replacing heating element on towel radiator
- Thread starter Cofty
- Start date
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It seems that I need educating (again!).
Reading this thread, we appear to be talking about a towel rail/radiator for a wet central heating system which also contains an electrical heating element (a bit like having an immersion heater in a usually-gas-heated hot water cylinder). Is that the case? If so, it's an animal that I didn't know existed - although I guess it's logical enough (for warm summer towels!)
Kind Regards, John.
Reading this thread, we appear to be talking about a towel rail/radiator for a wet central heating system which also contains an electrical heating element (a bit like having an immersion heater in a usually-gas-heated hot water cylinder). Is that the case? If so, it's an animal that I didn't know existed - although I guess it's logical enough (for warm summer towels!)
Kind Regards, John.
Hi John.
Our house - its central heating with combi boiler. In our bathroom, we have a towel rad. That towel rad has been wired up to on-off switch and has its own heating element wired up. Its also connected to the CH.
So yes, I think it is as you say. But a lot of towel rads have a heating element within them, so you can heat the rad separate from the CH. Not a rare beast, but a common set-up I thought?
Our house - its central heating with combi boiler. In our bathroom, we have a towel rad. That towel rad has been wired up to on-off switch and has its own heating element wired up. Its also connected to the CH.
So yes, I think it is as you say. But a lot of towel rads have a heating element within them, so you can heat the rad separate from the CH. Not a rare beast, but a common set-up I thought?
Yes, they act as a normal radiator (very hot) when the central heating is on and with electric element (only about 150W (150)) they dry the towels and if left on get quite warm.
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Thanks, guys, for confirming what I had assumed from reading this thread. It does seem a totally local concept - I'm just surprised that I've never come across such beasts! I'm familiar with ordinary 'wet' ones, and also oil-fileld electric (only) ones, but I obviously haven't lived enough to see these 'hybrids'!
Kind Regards, John.
Kind Regards, John.
Turning the mains mains water supply may not make any difference to the water in you system.
This will depend on the type of system you have though, do you have a boiler?
Indeed there should be two valves either side of the radiator tails, sometimes they are both functional and other times you will have control valve and a dummy as already mentioned, the dummy could well just have a pop off or screw off cap, this can be isolated by the use of a small spanner, pliers or grips etc...
My reasoning behind closing all the rad valves is two fold, one is an assurance that you don't have extra water draining if the valves are not closed properly on removal and also in case the valves are faulty and not closing fully and still allow water to flow under pressure.
When draining the towel rad, it is a good idea to help the release of water by undoing the the bleed valve too, this releases air pressure.
You will need something a container to catch the water, ideally at both valve points, I find paint trays very useful for this and I would have a bucket handy to poor the drained water in as the container may fill up a few times, but don't let it over fill, make sure you can remove container without spillage. Also have a sponge and cloth at the ready just in case.
Might be worth wrapping some dry cloth around the tails of the rads to catch any trickles.
Also another tip would be to wrap something around the valve nuts, so you don't damage them with the spanner on removal and replace, I use insulation tape.
When the rad is fully drained, tighten the bleed valve back up, remove the rad and tilt slightly, so any remaining water will trickle in to nearby container, then flip over.
Leaving the wire unconnected until you have replaced the elements is for
a few things; safety against accidental powering up electrics, prevent damage to cable and element, twisting cables, ease of fitting the element and also the cable may come loose if you have connected them first, when you fit the element back.
This will depend on the type of system you have though, do you have a boiler?
Indeed there should be two valves either side of the radiator tails, sometimes they are both functional and other times you will have control valve and a dummy as already mentioned, the dummy could well just have a pop off or screw off cap, this can be isolated by the use of a small spanner, pliers or grips etc...
My reasoning behind closing all the rad valves is two fold, one is an assurance that you don't have extra water draining if the valves are not closed properly on removal and also in case the valves are faulty and not closing fully and still allow water to flow under pressure.
When draining the towel rad, it is a good idea to help the release of water by undoing the the bleed valve too, this releases air pressure.
You will need something a container to catch the water, ideally at both valve points, I find paint trays very useful for this and I would have a bucket handy to poor the drained water in as the container may fill up a few times, but don't let it over fill, make sure you can remove container without spillage. Also have a sponge and cloth at the ready just in case.
Might be worth wrapping some dry cloth around the tails of the rads to catch any trickles.
Also another tip would be to wrap something around the valve nuts, so you don't damage them with the spanner on removal and replace, I use insulation tape.
When the rad is fully drained, tighten the bleed valve back up, remove the rad and tilt slightly, so any remaining water will trickle in to nearby container, then flip over.
Leaving the wire unconnected until you have replaced the elements is for
a few things; safety against accidental powering up electrics, prevent damage to cable and element, twisting cables, ease of fitting the element and also the cable may come loose if you have connected them first, when you fit the element back.
I have a similar problem - element has gone on dual fuel radiator. Looking at this thread is it really that simple to replace the element? For example:
1. Turn off water and isolate towel rail.
2. Turn both towel rail valves to off.
3. Open bleed valve.
4. Remove element and drain.
5. Replace element.
6. Turn it all back on.
I am comfortable with all these steps (if they're right) but don't want to screw up the rest of our central heating system in the process. Are these steps right and is there little risk of causing a problem elsewhere in the system?
1. Turn off water and isolate towel rail.
2. Turn both towel rail valves to off.
3. Open bleed valve.
4. Remove element and drain.
5. Replace element.
6. Turn it all back on.
I am comfortable with all these steps (if they're right) but don't want to screw up the rest of our central heating system in the process. Are these steps right and is there little risk of causing a problem elsewhere in the system?
You don't need to turn off the water if you're happy your two lock shields will close.
1. turn off two valves (two lockshields / one trv, one lock shield) - make a note of how many turns the lock shields take
2. open bleed valve
3. remove element and drain
4. replace element
5. open lock shield(s) - same number of turns
6. close bleed valve (quickly)
The theory is pretty similar to removing a rad without draining down the CH system.
You will dilute the inhibitor in your CH system a little bit, but assuming it's only a fairly small rad, I wouldn't worry too much.
If you have an unvented system, you may need to check the pressure too once you've refilled the rad, and perhaps top up (make a note of the working pressure beforehand)
1. turn off two valves (two lockshields / one trv, one lock shield) - make a note of how many turns the lock shields take
2. open bleed valve
3. remove element and drain
4. replace element
5. open lock shield(s) - same number of turns
6. close bleed valve (quickly)
The theory is pretty similar to removing a rad without draining down the CH system.
You will dilute the inhibitor in your CH system a little bit, but assuming it's only a fairly small rad, I wouldn't worry too much.
If you have an unvented system, you may need to check the pressure too once you've refilled the rad, and perhaps top up (make a note of the working pressure beforehand)
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I made a mistake. I turned off the lock shield valve and tested draining the water in radiator that no more water was coming out. However over night the TRV opened and water poured out. There are caps for the TRV that can be used to manually control them but only found out latter. But a bit of luck it was in wet room so only problem was needed to refill system with inhibitor.
The combi boiler comes in three types. You can still get open vented, with the closed vent some work on pressure others on water flow. With the latter you can get just lower floor working where water has leaked. If there is a leak with latter than you may be unaware there is no water in a radiator. With the pressure sensing boiler stops working so one is alerted but too easy with flow switch type for air to get into top of radiators.
In most houses a leak will always seem to empty one radiator first where ever the leak is. Should that be the towel rail that is clearly a problem. Often no TRV fitted to towel rail so in summer any leak tends to drain up stairs towel rail first.
So to me first thing to check if a element has gone down is was there water in the towel rail. I have never worked out why there is a flap covering the pressure gauge on the boiler? Likely I will notice pressure drop if there was no flap but opening flap to check I just don't do it.
With open vented systems leaks can be air in as well as water out. The venturi effect can draw in air, also new water contains gas which will be released when it gets hot so that gas can also end up in one radiator.
In theroy we should not get thermosyphon but in practice I found if the heater is switch one with a cold system OK but should the central heating kick in while the heater is on it can start the thermosyphon off and it will then continue to work heating other radiators.
The combi boiler comes in three types. You can still get open vented, with the closed vent some work on pressure others on water flow. With the latter you can get just lower floor working where water has leaked. If there is a leak with latter than you may be unaware there is no water in a radiator. With the pressure sensing boiler stops working so one is alerted but too easy with flow switch type for air to get into top of radiators.
In most houses a leak will always seem to empty one radiator first where ever the leak is. Should that be the towel rail that is clearly a problem. Often no TRV fitted to towel rail so in summer any leak tends to drain up stairs towel rail first.
So to me first thing to check if a element has gone down is was there water in the towel rail. I have never worked out why there is a flap covering the pressure gauge on the boiler? Likely I will notice pressure drop if there was no flap but opening flap to check I just don't do it.
With open vented systems leaks can be air in as well as water out. The venturi effect can draw in air, also new water contains gas which will be released when it gets hot so that gas can also end up in one radiator.
In theroy we should not get thermosyphon but in practice I found if the heater is switch one with a cold system OK but should the central heating kick in while the heater is on it can start the thermosyphon off and it will then continue to work heating other radiators.
Can someone explain to me why there are two valves? What does the 2nd do? How do I establish whether the 2nd is a dummy? I can still use/test the radiator when the central heating is on - the right valve seems to control whether the radiator warms up. What does the left valve do?
Last edited:
There are two valves because the radiator has an in and out - you can turn off both and remove the radiator.
They are both the same. The only 'dummy' part (lockshield - silly name) is the top of one which just rotates.
This valve should be set to balance the system and the dummy top prevents it being altered.
The other can be used to turn off and on.
They are both the same. The only 'dummy' part (lockshield - silly name) is the top of one which just rotates.
This valve should be set to balance the system and the dummy top prevents it being altered.
The other can be used to turn off and on.
Google for dual fuel towel rails.
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