One Radiator doesn’t work

Arsenal2019

Albermarle said:

ThisIsWeird said:

Most likely it's as you say, Arsenal.

The TRV heads often fail after 10 years or so of use, and one way they do this is by its mech remaining in the 'min' position, so keeping the valve closed all the time.

Examine the head; turn it upside down and look inside its bottom. See the plastic central bit that presses on the vale's pin? Ok, keep looking as you rotate the head from min to max and back - does it move in and out in a very obvious way? 'No', it's likely kaput, so all you need is a new head.

You can usually buy the whole valve for a similar cost to just the head, so I'd do so. Keep the valve bodies safe for fitting if/when your system needs a drain down.

I have the well known Drayton type TRV4 on some radiators. I would agree they last around 10/15 years, depending on how much that radiator is on. First they get very stiff and then fall off. The plastic inside has crumbled, it is always the same issue.
On other radiators I have the same TRVs as where there when we moved in 28 years ago, and they still work fine. I can not see any brand name on them, only the statement 'Made in Germany' , which maybe tells its own story as the Drayton ones are made in the UK. 

Hi. When I take the TTRV valve off and spin the thing as you said, the black plastic thing does not seem to move at all

also, when I hold it upside down, the black plastic needle thing is almost flush with the grip thing. As seen here 

Albermarle

OP - If you answer the question in @ThisIsWeird last post, that would help to get to the bottom of it.

Arsenal2019

Albermarle said:

OP - If you answer the question in @ThisIsWeird last post, that would help to get to the bottom of it.

Hello, I referred to that question in my answer (comment before yours / top of page 2)

when I turn the dial, the black plastic pin remains still / extended  and doesn’t move 

Arsenal2019

Also, I’ve been looking at new TRV’s.

Will I be Ok to get just the TRV head, or will I have to get a new head and the body too (as I’ll have no idea how to install the body and will have to get a plumber)

Thanks 

ThisIsWeird

Arsenal2019 said:

Albermarle said:

ThisIsWeird said:

Most likely it's as you say, Arsenal.

The TRV heads often fail after 10 years or so of use, and one way they do this is by its mech remaining in the 'min' position, so keeping the valve closed all the time.

Examine the head; turn it upside down and look inside its bottom. See the plastic central bit that presses on the vale's pin? Ok, keep looking as you rotate the head from min to max and back - does it move in and out in a very obvious way? 'No', it's likely kaput, so all you need is a new head.

You can usually buy the whole valve for a similar cost to just the head, so I'd do so. Keep the valve bodies safe for fitting if/when your system needs a drain down.

I have the well known Drayton type TRV4 on some radiators. I would agree they last around 10/15 years, depending on how much that radiator is on. First they get very stiff and then fall off. The plastic inside has crumbled, it is always the same issue.
On other radiators I have the same TRVs as where there when we moved in 28 years ago, and they still work fine. I can not see any brand name on them, only the statement 'Made in Germany' , which maybe tells its own story as the Drayton ones are made in the UK. 

Hi. When I take the TTRV valve off and spin the thing as you said, the black plastic thing does not seem to move at all
also, when I hold it upside down, the black plastic needle thing is almost flush with the grip thing. As seen here 

Good job - that's pretty convincing, then - it's kaput.

Yes, a modern Myson head should fit.

Q&As say it'll fit older Mysons, as long as they have a 30mm diameter securing collar - which yours looks to have.

https://www.screwfix.com/p/myson-plustrvheadw-white-trv-head/846PX?tc=IC4#product_additional_details_container

Of course, that would be too easy; there's also this one: https://www.screwfix.com/p/myson-trv2trvheadw-white-trv-head/125px I note that one reviewer of that last one says it fitted instead of their old head with a black base (like yours).

I'd take your head to SF and ask them the difference.

Then there's the decision of whether to go for the whole valve, and keep the body for later when your system is drained down for other work.

Either way, a good other thing to do would be to clean around that metal pin:

Better still, give it a spray with silicone lube, or a smear of silicone grease - that will lubricate it each time it moves up and down, and should help to prolong its life.

Arsenal2019

ThisIsWeird said:

Arsenal2019 said:

Albermarle said:

ThisIsWeird said:

Most likely it's as you say, Arsenal.

The TRV heads often fail after 10 years or so of use, and one way they do this is by its mech remaining in the 'min' position, so keeping the valve closed all the time.

Examine the head; turn it upside down and look inside its bottom. See the plastic central bit that presses on the vale's pin? Ok, keep looking as you rotate the head from min to max and back - does it move in and out in a very obvious way? 'No', it's likely kaput, so all you need is a new head.

You can usually buy the whole valve for a similar cost to just the head, so I'd do so. Keep the valve bodies safe for fitting if/when your system needs a drain down.

I have the well known Drayton type TRV4 on some radiators. I would agree they last around 10/15 years, depending on how much that radiator is on. First they get very stiff and then fall off. The plastic inside has crumbled, it is always the same issue.
On other radiators I have the same TRVs as where there when we moved in 28 years ago, and they still work fine. I can not see any brand name on them, only the statement 'Made in Germany' , which maybe tells its own story as the Drayton ones are made in the UK. 

Hi. When I take the TTRV valve off and spin the thing as you said, the black plastic thing does not seem to move at all
also, when I hold it upside down, the black plastic needle thing is almost flush with the grip thing. As seen here 

Good job - that's pretty convincing, then - it's kaput.

Yes, a modern Myson head should fit.

Q&As say it'll fit older Mysons, as long as they have a 30mm diameter securing collar - which yours looks to have.

https://www.screwfix.com/p/myson-plustrvheadw-white-trv-head/846PX?tc=IC4#product_additional_details_container

Of course, that would be too easy; there's also this one: https://www.screwfix.com/p/myson-trv2trvheadw-white-trv-head/125px I note that one reviewer of that last one says it fitted instead of their old head with a black base (like yours).

I'd take your head to SF and ask them the difference.

Then there's the decision of whether to go for the whole valve, and keep the body for later when your system is drained down for other work.

Either way, a good other thing to do would be to clean around that metal pin:

Better still, give it a spray with silicone lube, or a smear of silicone grease - that will lubricate it each time it moves up and down, and should help to prolong its life.

I’ve just bought the TRV from the first link you sent. That is due to arrive in store by Monday. HOPEFULLY that does the trick. I’ll get some silicone lube / grease to give it that extra bit.

thank you very much for your help. I appreciate you taking the time to help me out

FreeBear

If you are buying complete TRVs, also a good idea to add a bottle of inhibitor to the shopping list. If you need to drain the system down to replace the valve body, you'll need the inhibitor.

Eldi_Dos

@ThisIsWeird
I would not use silicon in a case like this, find it is better to rub a pencil up and down the pin and push pin up and down a few times, the graphite helps to keep pin mobile.My thinking would be when the pin is down over the summer months the silicon would then provide a resistance when it came time to have valve open again.

MCT56

Hi again, just take a flat metal object - such as an old spoon and test if you can physically push the silver pin in the valve down. Let it up and repeat several times. These pins need to move up and down. Yours looks to be in the up position in the photo and it should be pressed down by the plastic head when you turn it to control the temperature. If there is wear in the plastic contact area it won’t operate the valve. As suggested just get a new valve + head for a few pounds or try a head from one you know is working. Hope you get it resolved. 

Arsenal2019

MCT56 said:

Hi again, just take a flat metal object - such as an old spoon and test if you can physically push the silver pin in the valve down. Let it up and repeat several times. These pins need to move up and down. Yours looks to be in the up position in the photo and it should be pressed down by the plastic head when you turn it to control the temperature. If there is wear in the plastic contact area it won’t operate the valve. As suggested just get a new valve + head for a few pounds or try a head from one you know is working. Hope you get it resolved. 

Thanks for your response. I’ve got a near head ordered, I haven’t got the body thing as I weren’t sure I needed it.

so I’m hoping just screwing the new head on will do it ✅