water line going from supply to drain?? Help?

[newhomeowner]

I am hooking up a new faucet in the kitchen. I am replacing the old supply lines from the shutoff valve with stainless braided supply lines. On the current setup, there is a plastic valve located immediately after the cold-water shutoff under the sink. This valve is connected by a 1/4 line directly to the drain. It bypasses the sink, and I am not sure what this is used for? I would like to just remove it. Does anyone know what this is for?

Thanks

newhomeowner

 

[havasu]

A 1/4" line usually means either ice maker, reverse osmosis, or refrigerator water. I don't understand when you say "a 1/4 line directly to the drain", so if it is not what I have mentioned, you will either need to take a picture or describe it better to help you.

 

[SlowDrip]

The only time I have seen a 1/4" line connected directly to a drain is when dealing with an old floor drain that does not see much water. The line is usually fed from the laundry faucet, but sometimes from the furnace dehumidifier and keeps the drain moist to reduce gas.

It sounds like you have a similar hookup but for some reason it is hooked up below your sink. Perhaps you have no trap?

 

[majakdragon]

I agree that it is being used as a trap primer. This is used to keep water in seldom used traps to prevent sewer gases from entering the house. Most are set up to add water every time a faucet or fixture is turned on, not manual.

 

[phishfood]

I could be wrong, but I am thinking that the line does not actually tie into the drain. It probably comes out of the wall right beside the drain line, and from there it goes to an icemaker connection at the refrigerator location.

It would help immensely, though, if you could post a picture of this.

 

[SlowDrip]

I agree, phish. The conection point is exactly where you would hook up an icemaker.

Now...here is a bit of an odd idea but I could see this happening, so bear with me:


Someone at one point had an icemaker hooked up but eventually it was replaced by a fridge model without an icemaker. Whoever replaced the appliance didn't know how to cap the fitting and/or didn't want to take the effort to replace the copper line above the shutoff so they simply ran the line into the drain.

This is the "Ah, screw it" method of plumbing that I could easily see happening.

 

[newhomeowner]

Thanks for all of the input everyone. I'm thinking that it probably was at one time used to feed something else like an icemaker. We do have a fridge with a water hook up and icemaker. We also have a dishwasher, and the undersink plumbing does have a trap... but this wasn't for any of those. So I looked a little more closely, and you can see the a hole in the cabinet base with the same 1/4 inch blue tubing just below the surface. It has been cut and re-routed directly into the drain. Someone must have been using it for something else and done the "ah screw it" method, by just cutting the line and feeding it into the drain system, because the line litterally looped directly from the copper supply to the pvc drain system. If I would have opened tha valve on this line it would have been constantly flushing water down the drain.

So I removed the whole supply line at the shut-off and replaced it with braided stainless, and also changed out the pvc parts where the line had been tapped into the drain, effectively removing the whole contraption. thanks again!!!

 

[havasu]

Newhomeowner, thanks for letting us know the outcome. Feel free to stay in touch if you need anymore help!

BTW...Winner, winner, chicken dinner to Slow Drip for correctly answering his question correctly!

 

[phishfood]

That is scary!!

 

[havasu]

That is scary!!

I agree....I wonder what other repairs "newhomeowner" will have in the future?

 

[SlowDrip]

Glad you noticed it before you put hundreds of dollars of water down the drain.