Radiator gets hot without heating on

psd99

psd99

psd99

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I think the plumbing went wrong somewhere..

my towel radiator in the bathroom gets warm, when my boiler turns on for the hot water.

the radiator also works with the heating on etc, I found a temporary solution to turn the radiator off.

What could be the reason for this and how can it be corrected? Also, what side is the temperature control and water control for the radiator?
 
are we talking hot or just tepid and where is the boiler? It's not uncommon for modern combis to dissipate heat into the central heating system so the nearest radiator will often get a little warm when you run a bath/shower.
 
a1ex2001 said:
are we talking hot or just tepid and where is the boiler? It's not uncommon for modern combis to dissipate heat into the central heating system so the nearest radiator will often get a little warm when you run a bath/shower.
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slightly warm not very very hot

actually I got a system boiler with a tank

this radiator is:

a. closest to the hot water tank
b. closest to the boiler itself

but we don't use that shower and or hot taps much in the WC.
 
could be the motorised valve is slightly out of position when it moves into position for hot water only. therefore a small amount is getting through into the central heating.

if the plumbing wasn't done right then it would be geting a lot hotter than just slightly warm. it would be the same heat as your hot water.
 
Psycho Sonny said:
could be the motorised valve is slightly out of position when it moves into position for hot water only. therefore a small amount is getting through into the central heating.

if the plumbing wasn't done right then it would be geting a lot hotter than just slightly warm. it would be the same heat as your hot water.
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Would agree with this if the plumbing was significantly wrong you'd be getting much more than one slightly warm radiator, get someone round to have a look.
 
Almost certainly the diverter valve which directs the water to either the radiators or hot water, as required. its probably got stuck either through the valve failing or gunk bunging it up.

Needs an engineer visit most likely.
 
i wouldn't bother personally. wait until it fails completely then get it replaced. it's probably a little stiff. nothing to worry about.

i was told to replace a 3 way valve with 2 x 2 way valves as the 2 way valves are much more reliable. it's additional cost and hassle. so i just replaced it with another 3 way valve but of a better make. they however are a problematic part they will fail given enough time. it's a £30 part. getting someone out to look at it will cost you hundreds of pounds likely.

forget about it. you can change it yourself if you watch a youtube video.
 
diverter valve? what... so soon
it's a brand new setup well 6 months ago now

I can live with it but I'll ask the guy who set this all up!
 
psd99 said:
diverter valve? what... so soon
it's a brand new setup well 6 months ago now

I can live with it but I'll ask the guy who set this all up!
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it's probably stiff and needs loosening slightly. it's not worth worrying about.

british gas sometimes offer a free check up or service to as part of a deal. i got one with my mortgage provider. he loosened mine up but it was failing all the time. it's now knackered and i adjust it manually when i want the heating on.

they are a common replaceable, it could fail soon or last 20 years but just be a little stiff.
 
Psycho Sonny said:
it's probably stiff and needs loosening slightly. it's not worth worrying about.

british gas sometimes offer a free check up or service to as part of a deal. i got one with my mortgage provider. he loosened mine up but it was failing all the time. it's now knackered and i adjust it manually when i want the heating on.

they are a common replaceable, it could fail soon or last 20 years but just be a little stiff.
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you are probably right sonny

no point worrying about it
doesn't do much harm just wanted to know the reason why this happens only to that radiator and not others.
 
psd99 said:
you are probably right sonny

no point worrying about it
doesn't do much harm just wanted to know the reason why this happens only to that radiator and not others.
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the reason why it happens to that radiator and not others is because it's the first one in the chain.

since it's only a little amount of heat. it all gets dissipated by that radiator so by the time it reaches the next radiator in the chain there is no heat left to dissipate.

if you think about radiators as being a chain in which they are all linked in a circle. what usually happens is heat is pushed from one end of the chain to the other. this is why the first radiator in the chain is usually the hottest and the further away the coldest. your then supposed to use the trv's in such a way they all balance out. so the one closest to it would be on a low setting. ones in the middle on a middle setting and further away on a high setting. that isn't exact it's just to provide an example of how it's intended to work.

so this should explain why it's the one closest to it getting hot and the others aren't.

if you turn your heating on you should notice that one getting hot quicker than the others too.
 
good shout I will test it out

so what's the deals with the controls?

as I look at the radiator what does the left hand control do vs the right hand?
they are not labelled u see.
 
psd99 said:
good shout I will test it out

so what's the deals with the controls?

as I look at the radiator what does the left hand control do vs the right hand?
they are not labelled u see.
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not entirely sure what your talking about. i also cannot see any pics if you have posted them due to a firewall. i'll be able to see them when i get home. otherwise if you haven't posted pics could you post some?

google and youtube is your friend tbh. last year i knew nothing about central heating but i made it my purpose to figure it all out rather than paying some guy £60 an hour to tell me something i know isn't working is broken. it's all quite simple tbh. i'm terrible at DIY as well but I have been manually adjusting my 3 way valve for the past year after i found it it's temperamental. sometimes it works sometimes it doesn't.
 
Traditionally, bathroom towel rails were plumbed into the same loop as the hot water tank heating coil. That way you got you got a warm towel rail all the year round, not just when the heating was on.
 
Unlikely to be the diverter valve on a system with a system boiler and hot water tank as it won't have one it will be either a 2 port or 3 port valve, easy way to tell these are passing is feel the pipes on the feed to the raditors/tank

It sounds more likely reverse circulation when heating the hot water tank, if the return from the heating pipe work is closer to the boiler than the return from the tank reverse circulation can occur. Only a small portion of water reverse circulates which results in the first radiator getting luke warm. I have seen this mistake made in several new builds.

Easiest way to tell is turn on the heating and take a note of what pipe gets hot first on the affected radiator/towel rail then checking this when the system is heating the tank if they a different you have reverse circulation. You can sort this with a re pipe or a one way valve, although a towel radiator getting warm sounds an advantage as your towels will get dried all year round. Some systems have this by design with the towel rails getting heated with the hot water. I don't think your system is setup this way as it would be piping hot.
 
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good points guys
perhaps this is advantageous, but just in the summertime when it is extra hot it would be irritating. Guess I can turn it off then.


I will check exactly how hot it is but it's not a new build but a new bathroom for sure.
 
In my 10 year old home with 3 zones (2 central heating, 1 hot water) all radiators in the bathrooms come on with either the hot water or the central heating, apparently some plumbers do this by putting the bathroom rad circuit in before any isolation valves as it is assumed people want bathroom radiators on to dry towels etc. at any time of the year.

Personally if I was designing it, I would just put the rads on whatever floors circuit they appear on (and certainly not before the hot water circuit), but hey ho.

As suggested above, I just turn them off with the TRV during the summer.
 
Psycho Sonny said:
the reason why it happens to that radiator and not others is because it's the first one in the chain.

since it's only a little amount of heat. it all gets dissipated by that radiator so by the time it reaches the next radiator in the chain there is no heat left to dissipate.

if you think about radiators as being a chain in which they are all linked in a circle. what usually happens is heat is pushed from one end of the chain to the other. this is why the first radiator in the chain is usually the hottest and the further away the coldest. your then supposed to use the trv's in such a way they all balance out. so the one closest to it would be on a low setting. ones in the middle on a middle setting and further away on a high setting. that isn't exact it's just to provide an example of how it's intended to work.

so this should explain why it's the one closest to it getting hot and the others aren't.

if you turn your heating on you should notice that one getting hot quicker than the others too.
Click to expand...

TRV's are set to provide a room temp. Not a radiator temp. If you turn the first rad down via the TRV then the room wont heat up.

You balance via the Lockshield valve NOT the TRV
 
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