What have i done wrong

[harlow]

I removed the radiator before the council plastered our walls so when they finished they fitted the radiator back on but they never used any ptfe tape and the radiator didn't leak. So i removed the radiator to decorate and when i fitted it back on i didn't use any ptfe tape and i had a leak. So should i remove the radiator and use ptfe on the threads or should i just use boss white on the chamfer of the valves and don't use ptfe tape as i seen someone just use boss white on he chamfers on the valves on a video on youtube.

 

[TicklyT]

If the leak is on a compression joint, a wipe of sealant on the pipe olive will probably do the job. There's no point in putting anything on the thread of a compression joint. It's the olive that does the sealing, the thread just holds everything together.

Brand new fittings usually nip up leak free without any sealant. Re-used ones often benefit from a little help from a bit of sealant.

If the leak is from the male iron adaptor where it is screwed into the radiator, they usually need more PTFE tape than you would ever imagine is possible.

 

[harlow]

The leak is not where the radiator valve tail screws in to the radiator it's where the nut screws on to the angled valve.

 

[muggles]

If that's the case then, as TicklyT has already said, putting PTFE on the threads will not make a blind bit of difference. You need a smear of jointing paste around the olive.

 

[tincup]

I suspect you have older 3/4 valve fitting and a smear of boss white on the chamfer is advisable. Hold the two mating surfaces together to ensure they are square then do the nut up.

HTH