Installing Kitchen Faucet, Leaks at RO Valve Adapter

[preston a]

Hi,

I'm in the process of switching out an old kitchen faucet for a new one. The sink has an adapter that splits the cold water between the reverse osmosis system and the faucet's cold water input. Even after I tighten down the faucet's cold water input into this adapter, it leaks out of the threads. Maybe I'm not tightening it down hard enough? When I look inside the adapter, there's no rubber seal, just a little metal lip, so I guess this is supposed to work with metal-on-metal contact.

I've included photos of this adapter, as well as the new and old cold inputs for the faucets.

Any help is greatly appreciated!

preston

 

[Terry]

If you have straight threads from a faucet, those seal with the rubber seal from a flex connector, or from the bell of a solid riser.
Putting tape on the threads doesn't do anything.

A compression fitting doesn't use tape either.
The only place you use tape, would be on a tapered pipe thread.

 

[Sponsor]

 

[preston a]

I'll go ahead and take the tape off. I'm still confused because I'm doing a simple switch out, and the old faucet connected directly to the top of the valve adapter shown in the photos and never leaked. Whoever set this system up decided not to use a flex line.

The only place I put tape was on the threads of the new faucet. Anywhere else you see tape , it was put there by someone before me.

 

[preston a]

Hi Terry,

Here's a photo of how the old faucet was configured, and how I installed the new one but experienced a leak.

What I'm wondering is if there should be some sort of rubber washer in this location:

I never saw any washer when I took the old faucet out, and checked the floor to make sure that it didn't fall out (like it got stuck to the cold inlet and fell off or something). Nevertheless, anything's possible and it may be missing a vital washer.

 

[Reach4]

What is that black ring inside your red circle?

 

[preston a]

The black ring is on the other end of the adapter, I think its for the inlet side. Anyhow, the threaded end would bottom out on the metal lip/ring before reaching that black plastic.

However, let me take another look. The black plastic may be the actual washer and it has possibly fallen down. If so I could fish it out possibly.

 

[preston a]

Nope, the black piece is for the other end.

 

[preston a]

Ok I went to Lowes and purchased a replacement adapter, and it works. The new adapter has a metal cone that form-fits with the respective cone in the cold inlet on the faucet. The old adapter probably didn't work with the new faucet because the old cold inlet made a unique physical imprint on the metal ring inside the adapter. That's my theory anyway. It turns out that these adapters do not need rubber washers.