t.r.vs still leaking

[FRANKIEJUNIOR]

i replaced 3 t.r.vs for a friend and theres a slight leak on 2 of them just behind the nut on the radiator side that tightens the t.r.v onto the rad. it only leaks when heating is turned on and then stops once it gets going. i have put p.t.f.e round threads and nipped up fairly tight without overtightening but still theres a very slight leak. the only thing i can think of is that i never replaced the threaded bar that screws into bottom of rad with an allen key. could it simply be that this needs replaced as the nut may have becom worn over the 15 years that the heatings been installed or should i have replaced them with new ones when i replaced the valves. any advice will be much appreciated.

 

[stargazer]

You could try and re-make the joints using a little more ptfe tape and finish off with a good dollop of the panacea of plumbing spread around the threads…….

 

[LUNAT]

HI

I would recommend that you replace radiator valve.
pay a bit extra and you can buy valve with `o` ring at the end
which gives perfect seal

 

[nickso]

i replaced 3 t.r.vs for a friend and theres a slight leak on 2 of them just behind the nut on the radiator side that tightens the t.r.v onto the rad. it only leaks when heating is turned on and then stops once it gets going. i have put p.t.f.e round threads and nipped up fairly tight without overtightening but still theres a very slight leak. the only thing i can think of is that i never replaced the threaded bar that screws into bottom of rad with an allen key. could it simply be that this needs replaced as the nut may have becom worn over the 15 years that the heatings been installed or should i have replaced them with new ones when i replaced the valves. any advice will be much appreciated.

there is no point putting ptfe onto the thread of the rad tail as this is not what seals the two parts together. as suggested use paste on the parts of the tail that seal together or replace the lot if it wont seal.