Bristan thermostatic mixer

[Luggsey]

Hi all, just installing a Bristan mixing valve.
On the hot and cold inputs it has non return valves that have a fibre washer between the NRV and the body of the valve.
Do I need to ptfe the threads as well of is the fibre washer enough?
Tried to upload a photo but there seems to be a problem with that for me today.
Tganks.
Paul.

 

[ShaunCorbs]

Fibre washer is good enough

 

[Luggsey]

Fibre washer is good enough

Thanks Shaun, just fitted it.
Cherrs.