Water joint leak

[RickH]

Have an under sink water filter - previously annual change of filter been simple.
This year it leaks slightly
Filter is as per attached pic and leaks very slightly at the face between the filter canister and top fitting. (Blue arrow)



There is an O ring in the Cannister - changed that ... still same leak, water is coming up around the threads.


Never needed it before but tried PTFE tape ... as the male treads are almost a square section I twisted some PTF and wound that in first then initially 10 turns of tape ... still leaked

Added another 6 turns on top - still leaks

My next thought is add some water potable sealer.

I have a container of plumbers gas & water jointing compund (non-setting) do you think this is the best option on top of PTFE tape
or the other option I can think of is Fernox LSX sealer.

There is no seal or washer between where cannister mates against top unit.

 

[cross thread]

Have you checked the length of the filter? Possibly to long and stopping the seal.

 

[RickH]

It's a standard 10" filter.
I'll remove filter and see if it seals without one installed.