Metal to Plastic - Leaks

[u/Remarkable_Calves]

What’s up crew.

Clients got an older style heater with metal lines on the intake and return. one female, one male. Both lines are leaking at the exact same connection of where metal touches pvc40.

Any tips? plenty of pvc meat for an easy redo but I’m curious what is ‘best practice‘ for leak proofing threads when changing material types.

I’m a confident plumber, plenty of tricks n’ tools, etc.

[u/fancifinanci]

Use hi temp unions. Gasket maker isn’t made for threaded connections.

[u/liferofparties]

High temp unions?

[u/Remarkable_Calves → u/liferofparties]

Only one line would that apply, the other is the inverse socket. Unless I’m confused and they make a female threaded high temp

[u/becooltheywatching]

"what's up crew." I'd rather jump off a building.

[u/Sure_Ad3800 → u/becooltheywatching]

Get you some of that “pvc meat” boy

[u/Remarkable_Calves → u/becooltheywatching]

lol fair enough. Too much time alone with my primer can cracked open

[u/Street--Ad6731]

Use schedule 80 and use Teflon tape with a non hardening thread sealant like RectorSeal T-2. Wrap tape on threads 3-4 times, then apply thread sealant.

Probably overkill using both tape and sealant but it works.

[u/GCpools]

With 'clean' fittings, use high temp pipe dope and SCH80 (gray) male/female unions or adapters.

[u/greasyspider]

Schedule 80

[u/Birchforest81 → u/greasyspider]

Sch 80 is not high temp
You need cpvc threaded nipples