I have a dedicated water filter faucet with a 3/8 female 'compression' supply line (parallel threads). I am interested in connecting a push-fit based filter system to this faucet, but I'm not sure how to connect the push-fit tubing to the faucet. The faucet supply looks like this: The most viable option at the moment seems to be the PP051223W stem adapter from John Guest. The problem I see with this is that the threads are NPTF but the faucet line has straight threads. Won't it leak? Is there a better way to connect 3/8 tubing to 3/8 compression faucet?
You will need two fittings to connect 3/8 tubing to 3/8 compression together. Use Teflon tape between the two fittings to prevent leaks, but don't use any on the compression fitting. Remove and discard the brass compression nut and brass compression ring/sleeve to connect your 3/8 hose.
John Guest - Straight Adaptor – Nptf Thread
Part No. PI011223S --- TUBE OD 3/8" --- THREAD NPTF 3/8"
BrassCraft - Compression Female Adaptor
Part No. 66-6-6 --- 3/8 in. O.D. Tube x 3/8 in. FIP