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View Full Version : Needle Valve for DIY RO


levic900rr
03-26-2021, 03:26 PM
Hey Team, I have a 2 membrane RO that I built for my little operation. I have plastic tubing but a brass needle valve on the concentrate line to provide back pressure. I have a hard time getting that to seal up properly. My thought is that the brass (or copper to be honest I'm not real sure) compression bushing wont properly seat against the plastic tubing. I've seen on youtube it looks like some people are just using a quick connect ball valve on their output line. Can anyone confirm or deny that? It just BARLEY drips but I hate having a leak, even a small one.

Thanks
wobbletop
03-26-2021, 03:41 PM
Do you have the inner ferrule installed in the plastic tubing?
BobMac
03-29-2021, 01:35 PM
I use these they work good, this company has a lot to choose from.

https://www.freshwatersystems.com/products/dmfit-control-valve-union-connector-1-4-push-in
levic900rr
03-30-2021, 07:28 AM
I do have the ferrule installed. Thanks for the link I'm going to order one!
Fun4stuff
04-03-2021, 10:15 AM
I use these they work good, this company has a lot to choose from.

https://www.freshwatersystems.com/products/dmfit-control-valve-union-connector-1-4-push-in

That looks perfect!

It took me awhile to get my needle valve working correctly. It kept leaking. I had to heat up tubing in boiling water and then use pliers to get it over the inner tube part and through the nut. Since I got it seated correctly it has been working perfectly.