Filter Installation Advice

Just installed a replacement filter housing (Culligan HD-950A) in a small country inn laundry application. The old one had been cross-threaded and generally abused over the years. The in and out plumbing was a mishmash of copper, brass and plastic, so I replaced all of it.

New plumbing is all 3/4" Pex, with quality brass ball valves and fittings. This required (brass) male x female reducer fittings on the filter's in and out ports, as they are 1" IPS. The installation is great except the there is a small drip from where each of the adapters enter / leave the filter housing.

Being a semiconductor equipment designer / builder, I prefer to use Teflon tape. And yes, I really do know how to apply teflon tape!

The problem is that the reducer bushing hex flanges are tight against the filter housing. This makes it impossible to further tighten them. Looking on-line, I see that this is kind of a common problem with this filter model.

I really do not want to put more tape (it already has 2-3 wraps) on the 1" male end of the bushings, so am considering removing the tape and using a pipe dope / sealant.

To my question: What is the best pipe dope to use in this application?

Other suggestions solicited and appreciated!

Most of those housings seal with a rubber seat, not by your threads. Your Teflon could be preventing you from reaching the rubber (If indeed there is one). I also hate threading brass/metal into plastic, it's common for something to go wrong there. Maybe try using plastic male adapters

Matt30:

Thanks for the reply!

No rubber seals in / on the Culligan filter housing. They specify 1" IPS males for the connection. On-line resources show quite a few leaks mostly traced to the threads in the filter housing being too deep. Seems the solution is to add more teflon tape. I might be forced to do that.

I absolutely agree with you on NOT using metal male fittings screwed into plastic female fittings. In fact, that is why I am replacing all the plumbing on this small system: The 'handyman' who did the original plumbing used metal nipples screwed into plastic ball valves. He screwed them so tight that they actually fractured the valve bodies.

He also used a couple of rolls of teflon tape, with 20 to 30 turns on each connection.

As to your suggestion, I could use 1" male X 3/4" female PVC reducers on the filter, but as far as I know, SharkBite fittings are not available in PVC, so I would still have a 3/4" (brass) male SharkBite adapter screwed into the 3/4" female end of the PVC adapter. Not acceptable construction IMO.

That is why I am looking for some better sealant.