CotswoldDoItUpper Posted February 18, 2022 Share Posted February 18, 2022 (edited) I’ve got my new rads in, plumbed, attached etc etc. I fill. Tails leak. I drain. I re-do tails with 12 clockwise turns of PTFE (previous was 6 turns) I fill. Tails weep. I drain. I clean and re-do tails with a good smear Fernox LS-X and PTFE tape. I fill. 5 of 6 fine (at 1bar, didn’t get to 2!) 1 horrendous. I drain. what next?!? More PTFE and more Fernox? Getting a bit pissed offed now. Not had this issue with other rads before. And obv no heating whilst it’s all off. Added pressure from SWMBO because she’s cold. Help! Edited February 18, 2022 by CotswoldDoItUpper SPG Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 18, 2022 Share Posted February 18, 2022 (edited) 21 turns of PTFE for me in most instances. You can tell if the threads are shit and the number of turns you’ve applied will not get any purchase, so if you’re a DIY’er then don’t beat yourself up……took me a couple of years to perfect this ‘sixth sense’. Are you stopping turning the stem in before the last of the threads of the stem reach the rad? Edited February 18, 2022 by Nickfromwales Link to comment Share on other sites More sharing options...
tonyshouse Posted February 18, 2022 Share Posted February 18, 2022 Tiny amount of smear in threads on rad, 10 turns of PTFE Over three three tiny smears on the threads of the tail, keep PTFE nice and tight. Once done not full pressure for 48 hours why do you nee 2 bar? Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 18, 2022 Share Posted February 18, 2022 FYI, I have been fitting valves to rads for north of 25 years, and have never ( not once ) had to or would use Fernox ( aka clear silicone ) to make a rad valve off. PTFE and experience is all you need, end of. Fernox is a bodge. 1 Link to comment Share on other sites More sharing options...
Marvin Posted February 18, 2022 Share Posted February 18, 2022 7 minutes ago, Nickfromwales said: FYI, I have been fitting valves to rads for north of 25 years, and have never ( not once ) had to or would use Fernox ( aka clear silicone ) to make a rad valve off. PTFE and experience is all you need, end of. Fernox is a bodge. Gas PTFE for me. Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 18, 2022 Share Posted February 18, 2022 2 minutes ago, tonyshouse said: Once done not full pressure for 48 hours We run to 2.5 bar cold on the day. If it can’t hold that we drain and redo. If it holds, we run it scorching hot and check again for final operation. 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 18, 2022 Share Posted February 18, 2022 Just now, Marvin said: Gas PTFE for me. Too thick for me, but mates of mine use it too. Link to comment Share on other sites More sharing options...
Marvin Posted February 18, 2022 Share Posted February 18, 2022 Less times round... Link to comment Share on other sites More sharing options...
Marvin Posted February 18, 2022 Share Posted February 18, 2022 (edited) 23 minutes ago, CotswoldDoItUpper said: I’ve got my new rads in, plumbed, attached etc etc. I fill. Tails leak. I drain. I re-do tails with 12 clockwise turns of PTFE (previous was 6 turns) I fill. Tails weep. I drain. I clean and re-do tails with a good smear Fernox LS-X and PTFE tape. I fill. 5 of 6 fine (at 1bar, didn’t get to 2!) 1 horrendous. I drain. what next?!? More PTFE and more Fernox? Getting a bit pissed offed now. Not had this issue with other rads before. And obv no heating whilst it’s all off. Added pressure from SWMBO because she’s cold. Help! Some radiators seem to have the bores a bit loose I have had this and needed to use hessian threads to seal them. Real pain in the ass tho. Edited February 18, 2022 by Marvin Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 18, 2022 Share Posted February 18, 2022 What make radiators are these? Link to comment Share on other sites More sharing options...
Marvin Posted February 18, 2022 Share Posted February 18, 2022 9 minutes ago, Nickfromwales said: What make radiators are these? Who? Me? They were a posh style. It was quite a while ago. It was almost as if they needed a https://www.screwfix.com/p/flomasta-compression-adapting-male-coupler-15mm-x-/69358?tc=IT2&ds_kid=92700055281954514&ds_rl=1249404&gclid=EAIaIQobChMIsN6-ppiK9gIVDOvtCh3QJg5EEAQYASABEgIcofD_BwE&gclsrc=aw.ds# to seal. Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 18, 2022 Share Posted February 18, 2022 Just now, Marvin said: Who? Me? No lol. The OP!! Link to comment Share on other sites More sharing options...
CotswoldDoItUpper Posted February 18, 2022 Author Share Posted February 18, 2022 Ok so I’ve done 21 turns as per @Nickfromwales advice. Here goes… they’re all from here: https://www.radiatoroutlet.co.uk/1800-x-383mm-white-vertical-traditional-3-column-radiator tails/valves from screwfix. TRVs from Hive. @tonyshouse I don’t need 2 bar, was just a check to see if they were holding pressure ok. Will pressurise properly when I know they work. 2 Link to comment Share on other sites More sharing options...
markocosic Posted February 19, 2022 Share Posted February 19, 2022 Threaded joints? Loctite 55 is more idiot proof than PTFE in my experience: https://www.henkel-adhesives.com/lv/en/spotlights/all-spotlights/news/loctite-55-intro.html Do make the wrapping tight. Don't make the wrapping too neat. Do "rough up" the threads. (scratch a file or hacksaw blade across them so that the outside of the threads feels rough) This will help the male thread "grab" the Loctite 55 and "drag" it deep into the joint. If the male thread is too smooth, especially with PFTE, then often the male part can "screw through" the PTFE as you tighten the joint so it looks like there's loads on but actually almost none of it is inside the joint. IF DIY, paranoid, and not in a rush then fill cold, whack it up to the maximum working pressure of the components (usually 10 bar for radiators and taps), top it up again after the initial stretch is taken out, then leave it under pressure overnight using something like this: https://www.ebay.co.uk/p/16028213862?iid=232209768745 That will find your weeping threads AND the compressions that you completely forgot to do up past fingertight / end feed copper that just has flux in but can hold up surprisingly well with just cold water at 1 bar or so! Link to comment Share on other sites More sharing options...
CotswoldDoItUpper Posted March 5, 2022 Author Share Posted March 5, 2022 Update. I’m giving up. I’ve put 30 turns on some and all followed all bits of various advice now. To the point where the olives are over compressed. Going to start again with new olives and nuts on these bad boys: https://www.screwfix.com/p/bsp-male-x-15mm-compression-rigid-trv-extension-piece-65mm-2-pack/10954 hopefully the rubber o-ring will stop any leaks! Will still liberally apply PTFE as a belt+braces approach! Link to comment Share on other sites More sharing options...
Onoff Posted March 5, 2022 Share Posted March 5, 2022 I used to use PTFE tape. Now I don't. I push the pipe into the fitting and smear with Jet Blue Plus. I then push the olive up to the fitting. I then apply more Jet Blue Plus. Only then do I put the nut on. Wipe off the excess with a rag. Haven't had a failure yet. Jet Blue Plus is even in my incoming water main joint that's at 8bar. It was the only thing that cured it leaking. Some favour other alternatives Steamseal etc. I'd always check it's suitable for potable water. https://www.wolseley.co.uk/product/center-center-jet-blue-plus-500-g/ Link to comment Share on other sites More sharing options...
dpmiller Posted March 5, 2022 Share Posted March 5, 2022 so where is it leaking then- the threads on the rad, or the compression fitting on the valve? Link to comment Share on other sites More sharing options...
CotswoldDoItUpper Posted March 5, 2022 Author Share Posted March 5, 2022 25 minutes ago, dpmiller said: so where is it leaking then- the threads on the rad, or the compression fitting on the valve? I have 3 weeping slowly from the tails one of which is also weeping from the compression joint. ugh. Link to comment Share on other sites More sharing options...
markocosic Posted March 6, 2022 Share Posted March 6, 2022 Quick smear of vegetable oil on the O-rings to help avoid shredding them as you tighten up the fitting. This is what loctite 55 looks like fwiw. Truly magical stuff. Premium valves will come with pre 'roughed up' threads to grip string and drag it into the joint. The compression nuts on the are inverted. More like a brake pipe flare nut. It helps to keep the pipe "straight" in the fitting - the bore that the pipe runs through is much longer so it's difficult to stuff up the joint by waggling the body relative to the pipe. I suspect your leaking compression will be caused by tweaking the valve body relative to the pipe as you fix it to the rad. Try to ensure that the valve body is held absolutely stationary as you tighten the compression. A smear of oil on the olive and the threads of the compression fitting will reduce the force that you need to apply on the spanners for the same joint pressure. This can help by making keeping the fitting stable easier. 1 1 Link to comment Share on other sites More sharing options...
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