Leaking Radiator Tails when fitting New Valves

[csxmodeller]

Hi all, hopefully someone can point me in the right direction. I'm fitting the valves to a new radiator. I fitted the rad tails into the rad using 3-4 turns of ptfe tape clockwise around the thread, both tails leaked. I've tried increasing the number of turns to 20 and then 30, both times both tails leaked.

I've never had trouble fitting tails before. Am I doing something wrong? Is there something else I could use instead of ptfe tape?

Not sure if it's relevant, but it's possible to screw the tails right into the rad. They don't tighten up against anything.

Thanks for any help, Lee

 

[AC Power]

Well, I would ensure all your mechanical connections of the NPT (National Pipe Thread) type. NPT threads are tapered, and only 3-4 wraps of tape is necessary.

 

[csxmodeller]

Looks like the tails were wrong. I got a pair of new ones from Screwfix and they work fine

 

[Doghouse Riley]

On the subject of leaking radiators, some leaks from radiators are hard to find, they are so small that they evaporate before you notice them. But over a few days, this can reduce the pressure in a combi system enough for it to trip out due to low pressure.
If the leak isn't in the radiators, connectors, or in the boiler itself, it's a big problem. You can live with it by topping up the system every few days, which isn't a big deal. Otherwise, it's carpets and floorboards up, searching for it in the pipework. A third option is the addition of, "Sentinel" the combi boiler equivalent of Radweld, to cure a small leak or at least reduce it to a manageable level.

 

[csxmodeller]

Thanks Doghouse