3 Water Lines Under Kitchen Sink

[atnet360]

I'm considering replacing the RO system under my kitchen sink and was doing a little recon. I was surprised to see I have 3 separate water lines under there. Any thoughts on why there would be three?

I am guessing that from left to right they are 1) Hot Softened Water 2) Cold Softened Water and 3) Cold Hard Water, but can anyone confirm?

Also confused about the 1/4" lines coming out of them. The 1/4" line coming from the middle valve feeds the RO system. The 1/4" line coming out of the right valve tees into the 3/8" line going up to the drinking water faucet.

Any ideas?

 

[Jeff Handy]

Your guess about the three lines sounds likely, but you will have to do your own line tracing, start by shutting off all the softener valves and see if any sink valves still provide water.

 

[atnet360]

Weird. Left and middle are both soft water. The one on the right must be disconnected or shut off upstream somewhere. I closed the valve, disconnected the 1/4 in line and reopened the valve, nothing came out.

Anyway, I've got what I need for my RO install, but still perplexed about the third valve on the right.

 

[Jeff Handy]

On the dead valve, what is it connected to under the sink?

You said you removed a line from it, where does that line lead to?

This sounds weird.

 

[atnet360]

In the picture--the valve on the far right--the only thing coming out of it is the grey 1/4 inch hose (you can see it in the picture), which tees into a larger 3/8 inch hose that comes from the RO system to the water faucet above. I disconnected the 1/4 inch hose from where it tees into the 3/8 inch hose, then opened the valve. Nothing.

 

[Rickyman]

That line on the far right could feed your ice maker/refrigerator from the RO water.