Compression cap to stop flow - is this the right approach?

[RobInToronto]

Hi! New here. Appreciate your advice.

I'm trying to DIY install an undersink water filter system. I have a dedicated cold water pipe for it but the water filter system that I bought comes with a connection that splits flow to allow for both a cold water tap and the filter tap. I'm wanting to cap off that valve so water only flows to the filter. I bought a compression cap for this purpose (see photos) - is this the best way to go about this? I worry that it might leak. Should I use teflon tape or put a rubber o-ring or something in it to make a better seal? Is there something else you'd recommend?

Thanks for your insights!

Rob

 

[Tuttles Revenge]

I found that those tend to leak without a rubber washer to compress against the threads. A better way would be to eliminate that leak path and purchase a fitting that has no unnecessary ports.

 

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[Reach4]

Also see https://terrylove.com/forums/index.php?threads/seal-compression-cap.17899/

That sink washer idea on #6 looks good.

 

[PlumbNuts]

I have a dedicated cold water pipe for it

If it is a dedicated cold water pipe, does it not have it's own shut-off? If it does then just don't use the provided two-way valve, connect directly to the shut-off.

 

[Jadnashua]

The threads on that valve are not tapered pipe threads...they're hose threads, so that requires a washer, just like your hose would outside, to make a seal. Tape or pipe dope might work, but probably not, and if it did, might not be a permanent solution.

 

[RobInToronto]

Thanks so much everyone! I'm definitely going to find a rubber washer to put under there. I really appreciate all your feedback. I'm still a plumbing newbie so I'm grateful for your support

 

[RobInToronto]

If it is a dedicated cold water pipe, does it not have it's own shut-off? If it does then just don't use the provided two-way valve, connect directly to the shut-off.

You're right - it does have its own shut off valve but the hoses that connect to it are different (the hose that came with the filter is much smaller relative to the existing connection). I'd have to find an adapter of some kind to connect to it. I might look into this too as a fix but will give the rubber washer a try first and see how that works out.