TRVs and PTFE vs Hemp

[shd1970]

Morning all

I’ve got a number of radiators that I’m about to change so planning to replace the TRVs also
Does anyone have any recommendations for some good TRVs please ?
Are the Drayton 4s still respected ?

Second question….what’s the latest view on what to use on the threads that go into the radiators so as not to get a leak…ptfe, hemp or something else ?

Thanks in advance

 

[oldbuffer]

1. I have found that recent TRV4's are prone to the head coming off rendering them useless.
2. Sealing tails (in personal order of preference):
2.1 PTFE - start at 15 wraps then more, occasionally fewer, as necessary. Cheapest.
2.2 Loctite 55 - gently "rough up" male threads, wraps as directed. Start at 12 wraps. Generally bullet proof.
2.3 Flomasta Pipe Thread Seal (Screwfix). Metal to metal only. Requires everything to be clean and grease free. Reasonable price per radiator if you do a good number. Expensive for one or two.

 

[shd1970]

Thanks for the reply @oldbuffer

Any thoughts on an alternative TRV please ?
I used the Draytons previously and they seemed fine/good but as you described I’ve had a couple recently where the plastic thread has almost disintegrated
No biggy but just wanted to see if there was a new kid on the block

I’ll have a look at the loctite as not seen or used that before as I’ve always used ptfe personally

I had some work done on a radiator some time back and the blanking plug has a brown gunge around it now so not sure what he used or whether there is a problem
That said that radiator is the one of the ones I’m go into place anyway

 

[JohnD]

I used to like TRV4 but now prefer the Drayton RAS C2

 

[fixitflav]

Thanks for the reply @oldbuffer

Any thoughts on an alternative TRV please ?
I used the Draytons previously and they seemed fine/good but as you described I’ve had a couple recently where the plastic thread has almost disintegrated
No biggy but just wanted to see if there was a new kid on the block

I’ll have a look at the loctite as not seen or used that before as I’ve always used ptfe personally

I had some work done on a radiator some time back and the blanking plug has a brown gunge around it now so not sure what he used or whether there is a problem
That said that radiator is the one of the ones I’m go into place anyway

Somebody on this site a while back recommended these, but I've no personal experience.

TRV pack Eclipse

www.imi-hydronic.com

 

[shd1970]

I used to like TRV4 but now prefer the Drayton RAS C2

You mean Danfoss @JohnD ?

 

[JohnD]

Oh yes

 

[shd1970]

@JohnD how would i include a drain valve with the Danfoss ?
From what I can see from screwfix item 49331, it doesn’t like I can unless I’m mistaken
My downstairs rads are fed from upstairs as I have concrete floors so needing to drain down ever would be a slow process

 

[JohnD]

If you're doing some plumbing work on the radiators, I'd add a full bore valve on a Tee to the pipe. Water will gush out much better than from a drain cock.

Putting it on the return pipe will keep it at a lower temperature.

A washing machine valve can have a hosepipe screwed onto it.
The Pegler ones are good quality and easily resist the temperature and pressure

Pegler Valve Washing - Search Results | Screwfix

Order pegler valve washing at screwfix.com. Free next day delivery available. Buy online & collect in hundreds of stores in as little as 1 minute. Free returns. 30 day money back guarantee.

www.screwfix.com

Best to add a cap nut in case it is accidentally turned on or fails.

Flomasta BSP Blank Nut 3/4" x - Screwfix

Order online at Screwfix.com. Brass blank nut. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

There are other varieties that are bigger but fine if out of sight. You'll notice the full bore ones look fatter in the barrel.

Pegler Valve Full Ball - Search Results | Screwfix

Order pegler valve full ball at screwfix.com. Free next day delivery available. Buy online & collect in hundreds of stores in as little as 1 minute. Free returns. 30 day money back guarantee.

www.screwfix.com

There are some very cheap ball valve around that are prone to leak.

 

[shd1970]

I’m replacing 3 downstairs radiators so taking the opportunity to give the system a clean also as my tf1 is picking up loads of crap so no inhibitor is in the system

 

[Madrab]

Valves of any type like that only fair well when the system is in good condition, if not then they will leak if used, its the same as older boiler isolation valves, even then for some reason ball valves don't fair well in central heating systems. I believe it has to do with what the seals and seats are made of, they aren't happy with the unique conditions found in central heating systems.

Drain offs are the best option IME.

 

[shd1970]

Thanks for your input @Madrab

Do you happen to know if Danfoss have a TRV with the drain valve built in ?

 

[Madrab]

I do believe that Danfoss do a tail (Drain off tail) with a drain off, you throw away the normal rad tail for the TRV and fit that one.

That aside, absolutely no problem with getting a lockshield with one built in too.