Leaks from 1"NPT male metal to female plastic.

Background :
Our house is plumbed with type M (thin wall) copper pipe and I am getting pinhole leaks - 1, maybe 2 year - enough to have me ripping it our and replacing it with Pex. The Pex manifold and home run pex tubing part is great, no issues there, but as I went down this route we decided to also put in a Crystal Quest whole house filter. The unit comes with male to male 1" NPT fittings, one end screws into a copper 1" NPT female to 1" copper sweat fitting (no issues there). The other end screws into the whole house filter and it is a male metal to female plastic fitting. The instructions are not to use any form of thread sealant - tape, dope etc. Well I followed these instructions and I have leaks on both the in and out sides. Should I be be looking at using some form of sealant despite what the instructions say ?

This is the unit in question : http://crystalquest.com/Qstore/Qstore.cgi?CMD=011&PROD=1154380041&ADMIN=YES

Any experience with this ? Suggestions ?

Thanks

Mark

non professional opinion

Personally, and as the hack that I am, I would put teflon tape on those pipe threads, even if they think you don't need it.

Why not call or e-mail crystalquest and explain what you're seeing and ask them what would be a good solution? They may well have a better idea.

Thanks, yes, I contacted them last night, waiting to hear back. Based on some other posts I saw I am thinking re-do with thread and paste (suitable for plastic). I'll see what they say.

As I loked at it though I realize though that I have 'hard wired' it in with sweat connectors and I am going to need to cut the copper to remove it and then put it back with a couple of compression fittings (think of the water filter as the bottom of a 'U' and the two tops of the U being the connection points). Back in the UK we had compression fittings with deformable copper 'olives' in them - I assume they have something similar over here. What are these called in the US ?

The other thing I realized is that I don't have a bypass - so I'll need to add another shut off valve and a couple of tee's (while I am at it)

fitting

Male metal to female plastic of any kind is usually a disaster waiting the happen. ANY corrosion on the metal side will create immense stress in the joint and that usually means that the female plastic piece has to expand and eventually crack. Unless there is a rubber gasket or "O" ring inside the joint it must have a sealant on the threads to help fill any voids caused by threading irregularities.

hj - do you recommend something different ? should I be making a male plastic thread with a male to male adapter and then transitioning to copper from that with a female to sweat copper fitting ?

Also I have read that compression sleeves (olives) are for one time use only and they will deform the pipe too - what should I e using if I want the connections to be dismantle'ble ?

You can install CPVC male adp. with a 6" CPVC nipple and then sharkbite connection to PEX or copper

svcalypso said:

The other thing I realized is that I don't have a bypass - so I'll need to add another shut off valve and a couple of tee's (while I am at it)

Click to expand...

Do the filter housings not have an integrated bypass to allow opening and changing out the filter elements?

svcalypso said:

Back in the UK we had compression fittings with deformable copper 'olives' in them

Click to expand...

Ferrule. There's one pictured here: http://en.wikipedia.org/wiki/Compression_fitting

No, they don't - my current single stage one does but it's plastic and tough to turn so I plumbed a copper bypass around that anyway years back. The bypass is also there in case - just in case - I have further issues with the unit. I can always splice a piece of copper in a jiffy but something like this, tats proprietary can't be fixed like that so I think for an hours work the bypass makes sense.



Thanks for the link to the wiki page, I'll go down to Republic plumbing on Saturday and get a couple of fittings.

bypass

The only way a bypass makes sense is if the filter also has valves on either side so it can be serviced while the bypass maintains flow to the building. There are several ways it could be done, but I have no idea what kinds of fittings are available in your area, or what the o.d. is of the plastic you are working with.