Help with radiator TRV’s

Auti

Hello - first of all getting a plumber is like gold dust so I need some help please. Have an old gas central heating system boiler changed about 17 yrs ago but rads/pipes/trv’s not so could be up to 30 yrs old. 

Have problems with trv’s as they sticking and a couple I do think are just broken as rad hot even when trv is at 0. I need to replace them (and a couple of rads).

Currently the trv’s are as in picture - Honeywell - as you can see they are yellow with age. I am hoping to replace with Drayton TRV4 classic. Is this feasible and do I need to replace the whole assembly inc the metal bit that goes into the rad or can I just replace the trv bit? I hope someone can advise as I don’t want to freeze or cause a flood  

tacpot12

I would suggest you get hold of a Drayton TRV4 head off of eBay and try it on your valves. It will probably fit as the majority of valves use the Honeywell screwthread If they don't, they replace them with more of the Honeywell VT15 valves (also available on eBay). The VT15 is a great valve. I used them at home and in my rental properties, but they do eventually cease working after many years.

You don't need to replace the valve body - the head just unscrews and the Drayton will probably screw straight back onto to the valve body. If the valve body is sticking, then applying a quirt of WD40 to the pin and operating the pin gently with a steel tool (e.g. the face of a hammer) can free the valve up so that the wax motor in the head can operate it again. Don't hit the pin with a hammer as this can cause leaks. Gently does it. 

Lots of videos on YouTube about doing all of the above. 

Albermarle

There are two parts to a TRV. The head - the visible plastic part that you turn, and the actual thermostatic valve that is in the metal part joining the inlet pipe to the radiator. 
The plastic part can deteriorate with age and I have had some become 'crumbly' inside and they feel wobbly.
Replacing them is easy, but replacing the metal valve is more of a job. Often these valves get stuck and some tapping and a drop of lubricant can often work .
It may be worth you knowing that the old TRV's I have ( > 25 years old) look a bit like yours and work fine still, but most of the newer Drayton TRV4' have had to be replaced at some point due to the plastic deteriorating.

FreeBear

tacpot12 said:

I would suggest you get hold of a Drayton TRV4 head off of eBay and try it on your valves.

I've got a couple kicking around here that I'm not going to use (they came "free" with some radiators). @Auti Ping me a message and we can arrange getting one to you.

ThisIsWeird

Auti said:

See that large knurled collar? Open the TRV to 'max' (to loosen any tension on the internals), and unscrew that collar anti-clock as you look down from above. Your head will come off.

Measure - if you can - the diameter of the exposed threaded section of the valve body. If it helps, you can do that by wrapping a piece of paper around it, marking the circumf on the paper, unfurling, and dividing by 3.14.

Also post a photo of the exposed valve top and pin.

As explained by others, try pushing this pin down using something to protect your thumb - it'll be against a strongish spring. If in good order, it should move down smoothly, stop with a positive 'thunk', and spring back up instantly when released. If it's good, then replacing the heads should be all that's required, and that is a much easier job. We can also hopefully point you towards suitable heads - possibly the Drayton, but we don't know.

Once you get a head that fits, I would personally - on such old valves - run a small bead of silicone grease around the pin's base, so that it draws a tiny bit down with it every time it's operated. That's the best lube for the rubber seal inside.

Anyhoo, pics!

Edit: The fitting seems to be M30 x 1.5mm

If you are looking to update the valve's appearance, then the Honeywell Valencia Classic has a good chance of fitting - it's also M30 x 1.5. But ask Honey first. Not cheap, tho'...

Plenty of your current VT15 heads available, from around £13 each.

You could even fit Smart heads and have remote scheduled control over them :-)

nofoollikeold

1. Even if the head of a different make / model of TRV fits the thread on the actual (chrome plated) valve, it doesn't mean the TRV will operate as it should.
2. The actual thermostatic capsule is in the removable head.  It is a sealed "piston" filled with wax or oil.  As it heats, it expands, and pushes down a pin to shut the valve.  The pin is in the body of the valve, and its length is determined by the manufacturer to work with the capsule.  If it is too long or too short for a different head, the TRV will not operate as expected. 
3. I have recently found a number of TRV4s fail, with the chromed "cap" part separating from the rest of the removable head, rendering the head useless.  
4. Personally, I would stick to Honeywell.  If you want to change the whole valve, I'd consider Honeywell, Danfoss or Pegler.   

Auti

@nofoollikeold - good point. Yet another thing to think about! 

Auti

ThisIsWeird said:

Auti said:

See that large knurled collar? Open the TRV to 'max' (to loosen any tension on the internals), and unscrew that collar anti-clock as you look down from above. Your head will come off.

Measure - if you can - the diameter of the exposed threaded section of the valve body. If it helps, you can do that by wrapping a piece of paper around it, marking the circumf on the paper, unfurling, and dividing by 3.14.

Also post a photo of the exposed valve top and pin.

As explained by others, try pushing this pin down using something to protect your thumb - it'll be against a strongish spring. If in good order, it should move down smoothly, stop with a positive 'thunk', and spring back up instantly when released. If it's good, then replacing the heads should be all that's required, and that is a much easier job. We can also hopefully point you towards suitable heads - possibly the Drayton, but we don't know.

Once you get a head that fits, I would personally - on such old valves - run a small bead of silicone grease around the pin's base, so that it draws a tiny bit down with it every time it's operated. That's the best lube for the rubber seal inside.

Anyhoo, pics!

Edit: The fitting seems to be M30 x 1.5mm

If you are looking to update the valve's appearance, then the Honeywell Valencia Classic has a good chance of fitting - it's also M30 x 1.5. But ask Honey first. Not cheap, tho'...

Plenty of your current VT15 heads available, from around £13 each.

You could even fit Smart heads and have remote scheduled control over them :-)





Thank you - sorry not sure if this is right way to quote.  The idea with silicone grease sounds good please could you tell me/point me in the right direction as to purchasing some. I have a feeling that if I go in and say I want some silicone grease I may end up with the wrong thing and not know (much prefer going in knowing exactly what I want so I get it right first time).

Also thank you for identifying my trv heads and the upgrade (I will check for compatibility) - I thought I could not get a direct replacement as they were so old. I will post a photo later today as I have jobs this morning.

I am not so worried now that I will flood the house

Apparently the body is ten characters too short (have just found out I can type here

ThisIsWeird

Auti said:

ThisIsWeird said:

Auti said:

See that large knurled collar? Open the TRV to 'max' (to loosen any tension on the internals), and unscrew that collar anti-clock as you look down from above. Your head will come off.

Measure - if you can - the diameter of the exposed threaded section of the valve body. If it helps, you can do that by wrapping a piece of paper around it, marking the circumf on the paper, unfurling, and dividing by 3.14.

Also post a photo of the exposed valve top and pin.

As explained by others, try pushing this pin down using something to protect your thumb - it'll be against a strongish spring. If in good order, it should move down smoothly, stop with a positive 'thunk', and spring back up instantly when released. If it's good, then replacing the heads should be all that's required, and that is a much easier job. We can also hopefully point you towards suitable heads - possibly the Drayton, but we don't know.

Once you get a head that fits, I would personally - on such old valves - run a small bead of silicone grease around the pin's base, so that it draws a tiny bit down with it every time it's operated. That's the best lube for the rubber seal inside.

Anyhoo, pics!

Edit: The fitting seems to be M30 x 1.5mm

If you are looking to update the valve's appearance, then the Honeywell Valencia Classic has a good chance of fitting - it's also M30 x 1.5. But ask Honey first. Not cheap, tho'...

Plenty of your current VT15 heads available, from around £13 each.

You could even fit Smart heads and have remote scheduled control over them :-)





Thank you - sorry not sure if this is right way to quote.  The idea with silicone grease sounds good please could you tell me/point me in the right direction as to purchasing some. I have a feeling that if I go in and say I want some silicone grease I may end up with the wrong thing and not know (much prefer going in knowing exactly what I want so I get it right first time).

Also thank you for identifying my trv heads and the upgrade (I will check for compatibility) - I thought I could not get a direct replacement as they were so old. I will post a photo later today as I have jobs this morning.

I am not so worried now that I will flood the house

Apparently the body is ten characters too short (have just found out I can type here

Ha-ha - double learning curve :-)
If you want to play safe with the fitting, then the original VT15 heads seem available, and at a reasonable price - that's the obvious solution. If you want to go 'modern', then ask Honey (or other manufacturer) if they are fully compatible; as NFLO says, the pin travel can vary. I don't know that the Valencia Classic will suit.
I'll link to a suitable grease when I get on my PC. It's good stuff to have in any case - lub'ing swivel tap spouts and stuff like that.
Yes, you can remove the TRV heads without any risk of water leaks.
A further thought - once you choose the replacement head, for the little difference in cost (sometimes none at all...), then buy the whole valve. Put the bodies aside somewhere, for the day your system is drained down for a different reason - the plumber can then swap the bodies in just 10 minutes each.
Whenever I replace an actuator head for someone, I buy the complete unit, and ask them to leave the body in a box near their cylinder, and to ask their plumber to swap it the next time drain-down work is carried out.

FreeBear

Auti said:

ThisIsWeird said:

Auti said:

See that large knurled collar? Open the TRV to 'max' (to loosen any tension on the internals), and unscrew that collar anti-clock as you look down from above. Your head will come off.

Measure - if you can - the diameter of the exposed threaded section of the valve body. If it helps, you can do that by wrapping a piece of paper around it, marking the circumf on the paper, unfurling, and dividing by 3.14.

Also post a photo of the exposed valve top and pin.

As explained by others, try pushing this pin down using something to protect your thumb - it'll be against a strongish spring. If in good order, it should move down smoothly, stop with a positive 'thunk', and spring back up instantly when released. If it's good, then replacing the heads should be all that's required, and that is a much easier job. We can also hopefully point you towards suitable heads - possibly the Drayton, but we don't know.

Once you get a head that fits, I would personally - on such old valves - run a small bead of silicone grease around the pin's base, so that it draws a tiny bit down with it every time it's operated. That's the best lube for the rubber seal inside.

Anyhoo, pics!

Edit: The fitting seems to be M30 x 1.5mm

If you are looking to update the valve's appearance, then the Honeywell Valencia Classic has a good chance of fitting - it's also M30 x 1.5. But ask Honey first. Not cheap, tho'...

Plenty of your current VT15 heads available, from around £13 each.

You could even fit Smart heads and have remote scheduled control over them :-)

Thank you - sorry not sure if this is right way to quote.  The idea with silicone grease sounds good please could you tell me/point me in the right direction as to purchasing some. I have a feeling that if I go in and say I want some silicone grease I may end up with the wrong thing and not know (much prefer going in knowing exactly what I want so I get it right first time).

You can get small tubes of grease from the likes of Halfords or Wilco - I find CopperSlip to be useful around the house. A PTFE spray is also very good for keeping things moving - Much better than WD40, especially when you have rubber seals to contend with.

WD40 is a water dispersant rather than a lubricant. It also contains chemicals than can ruin certain types of rubber - There is also a WD40 High Performance Silicone spray which (apparently) doesn't have the same problem as the Original WD40.

ThisIsWeird

I'll second what FreeBear says about PTFE - my other go-to lube.

I have a wee tub of this: https://www.ebay.co.uk/itm/234897007426 which claims is also has PTFE in it. No idea, but it seems to do sili stuff ok.

Or larger pots of sili: https://www.ebay.co.uk/itm/392006362139 (The stuff goes a loooong way, so will last years :-(  )

When you remove the head, check the pin action, and clean thoroughly around it and its base where it goes down. Then a tiny bit of the sili on your fingertip, and wipe it firmly around the pin's base to leave a complete ring. Each time the pin is activated by the head, it should draw in a tiny bit of sili to keep it all lubed. Sili won't dry out, and that area should also be free from house dust which could otherwise stick to any lube.