Problems Installing Radiator Tails

[WhatNext]

Hi

I was wondering if anyone could help ?

I am in the process of fitting Danfoss RAS-C2 TRVs and lockshield valves to my Myson radiators.

With the radiator removed from the wall, I cleaned out the 1/2" BSP tails on the radiators using a round wire brush. This allowed me to remove the old remaining PTFE tape together with some slight rust.

I first inserted the new radiator tails in the ends of the radiator dry to gauge how far it they would go when tightened up.

On removing the tail I then applied 6-7 wraps of Loctite 55 to the lower half to the radiator tail crossing the threads as I went, rather than following the thread grooves, as per the Loctite 55 instructions.

I started to make up the tail using a 16mm ring spanner - approx 8" long. With about 3 threads to go I needed to switch to a 10" Bacho adjustable wrench to tighten the tail all the the way up. It took a bit of force, but nothing which felt excessive, albeit this is first time that I have fitted radiator tails.

I have yet to refit the radiator and fill with water which will be the ultimate test, however I happened to notice that the nut of the radiator tail bound slightly when it was rotated around the tube of the radiator tail, which was not the case before I make it up ??

Is this normal / to be expected ?

Cheers

 

[jeff the gasman]

You've probably used too much muscle and distorted the tail. Let your wife tighten them.

 

[WhatNext]

Hi Jeff - thanks - I appreciate that you can not see the tails, but from your experience should I replace these ?

 

[John D v2.0]

Fill it up and see what happens. It's not likely to suddenly break in half, so if it doesn't leak it doesn't leak.

FWIW you might have beena bit shy on tape unless yours is gas tape or something. When I was doing our rads I used about 12 turns of tape, and tightened the tails up so they were still very slightly "on the tape" rather than grinding metal on metal with a long wrench. Maybe force of habit after fitting the outside tap - the first attempt was at a comedic angle until I tried again with more tape.
No leaks so far, most of them came from the other end of the tail where they have the compression type joint. My rule is if you don't know quite how far to tighten, you can always tighten 1/4 turn more later.

 

[WhatNext]

John many thanks

 

[John D v2.0]

No problem and good luck! And you'll be proud when you've finished

 

[James Carmichael]

Fill it up and see what happens. It's not likely to suddenly break in half, so if it doesn't leak it doesn't leak.

FWIW you might have beena bit shy on tape unless yours is gas tape or something. When I was doing our rads I used about 12 turns of tape, and tightened the tails up so they were still very slightly "on the tape" rather than grinding metal on metal with a long wrench. Maybe force of habit after fitting the outside tap - the first attempt was at a comedic angle until I tried again with more tape.
No leaks so far, most of them came from the other end of the tail where they have the compression type joint. My rule is if you don't know quite how far to tighten, you can always tighten 1/4 turn more later.

He's using Loctite 55, which is not PTFE tape. It's a highly fibrous string that frays asyou do up the joint, filling any gaps. Based on my experience of using it, the OP has applied it correctly. If anything, 5-6 turns is a little too much.

I agree with your rule wrt tightening.

 

[WhatNext]

James many thanks - how many turns of Loctite 55 would you recommend ? Would 5 be sufficient ?

 

[John D v2.0]

He's using Loctite 55, which is not PTFE tape. It's a highly fibrous string that frays asyou do up the joint, filling any gaps.

Thanks, I did not think to look up that tape! Yes I do indeed use bog standard PTFE.

 

[James Carmichael]

how many turns of Loctite 55 would you recommend ? Would 5 be sufficient ?

Kind of impossible for me to say - not least because I am only a DIYer, so have done 10s of not thousands of joints. I generally tend to go for around five or six turns. In my experience, that's enough to feel the string fluff up in the joint but without having to apply undue torque to tighten. Like you, my adjustable is about 250mm long. I've never felt the need to force it, and never had a leak, but I guess one man's force is another's light nip so I don't know whether you can read anything in to that!

Assumign I have read your question correctly, I can't for the life of me fathom how you could have distorted the valve end of the tail while doing up the radiator end. Still, on the assumption that the valve end is a compression fitting, I'd wager that if you can still get a nut and olive on, and if you can still get the end of the tail into the valve, it'll seal just fine. If you want to be paranoid about it, wrap some PTFE around the fitting face of the olive.

As has been said above, it'll either leak or it won't. If it seals, it seals. So, pragmatically, your options are:
(1) Try it; or
(2) Replace the tail if it worries you.

 

[WhatNext]

James - Many thanks - much appreciated. Did you find that the Loctite 55 was water tight on the first attempt ?

Did you apply the Loctite 55 to the lower half of the radiator tail ?

I am also confused as to how the radiator tail distorted as the end was free to rotate ??

I look forward to hearing from you.

 

[James Carmichael]

James - Many thanks - much appreciated. Did you find that the Loctite 55 was water tight on the first attempt ?

Yes

Did you apply the Loctite 55 to the lower half of the radiator tail ?

I am not sure I understand this question - what's the "lower half of [a] radiator tail?"

I am also confused as to how the radiator tail distorted as the end was free to rotate ??

Well, if you don't know, then I suspect no-one knows, as whatever happened, you did it!

Over and out on this thread for me now - stuff to get on with. Good luck with it ...

 

[WhatNext]

James - many many thanks - one very last question - when I said the lower half, sorry, I meant the first of the threads up to half way.

I understand that the fitting on the radiator is 1/2" BSP, while the radiator tails are 1/2" Taper Thread.

My logic for applying it to the first of the threads up to half way, was to prevent the Loctite 55 from being visible once the radiator tail was fitted.

Cheers and best regards.