Worcester 240 leaking between diverter valve and heat exchan

[LJINNO]

I replaced the diaphragm in the diverter valve in my worcester 240 .
Now, the pipe leading to the heat exchanger is leaking badly.
The one pipe slides inside a slighly bigger pipe-this is where the leak is.
What kind of seal is it, is it an oring?
please help asap
Thanks

 

[Agile]

Its an "O" ring seal and they always leak!

Its easiest to just replace it at around £10.

A few weeks ago I was stuck without one and managed to get it to stop leaking by cleaning, lubricating with silicone grease and wrapping about three turns of PTFE around the ring.

Tony