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Dec 18, 2012
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After four years of not leaking, the 10mm compression joint on one of my son's TRVs has decided to weep -resulting in combi pressure loss within a few days. I have slackened it off a tad and retightened and will keep an eye on it. It was already very tight, so I am expecting it to still weep and to have to undo it completely in the near future. I guess this will mean having to drain the system? My plan would be to remove old olive, replace with a new brass one and a dollop of paste. Is that the best way to do it? Or would a dollop of paste be enough? I'm pretty sure no paste was used when the plumber did the valves.
 
You might be better to take the easy way and just wrap a few turns of ptfe tape around the olive and gently nip the nut up again, if the olive seems okay. A very slight smear of paste would do no harm also, - I use V2 Jet Lube.
Maybe the pipe or valve had got a knock and it started a weep. Brass olives are better on heating pipes, but the 10mm copper is very soft. A pipe support originally would have helped the joint. On the very few occasions I had to use 10mm on heating, I preferred to use 15mm rad valves and have a soldered reducer 10x15mm (15mm male end type) to go to valve so that the copper was hard and would withstand movement
 
You guys are amazing - always so helpful! Greatly appreciated. I will give it a go with tape - which I have, and Jetlube V2 - which I also have. Never used Loctite 55.
 
55 cord is for threaded joints...

Ptfe or jet lube on an dodgy olive...

If it's an old crimped reducer on the 10mm then may need cutting out & repairing as these leak when knocked...
 
I shall let you know the outcome when I get round to doing it - when the weather warms up, so that will be on August 3rd at 14:05 until 14:15.
 
loctite 577 on threads. 10mm pipe is very malleable so a few wraps of tape should sort it, gas tape would be even better
 

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