[ToroMorro]

Howdy folks,
My house was built on a concrete slab in Cali in the late 90's. Copper pipes all run through the slab and stub upwards inside the walls.

Water heater and water softener are plumbed in the garage right next to each other, using 3/4" pipe.

Right next to the water heater, about 18" away from the water softener, is a 1/2" copper stub sticking out of the wall with a cap soldered on it. I can tell nothing has ever been hooked up to it because it has wall texture sprayed on it from the original construction.

It cannot be for laundry, because that's inside the house and has all the plumbing it needs. I doubt it would be for a laundry/garage sink because there is no room for it, and no drain for one.

That's my "Mystery Nipple"...any ideas on the plumbing application for it?

Cheers,
ToroMorro

 

[rjniles]

For a hot water recirculating pump?

 

[joed]

Spigot in garage for washing cars?

 

[ToroMorro]

For a hot water recirculating pump?

So if it is for a recirc pump, there would be an extra stub in the wall under the kitchen sink, right? (Kitchen is farthest away from water heater.)
The house also has one of those external Grundfos recirc pumps on the hot water heater, with the funky check valve under the kitchen sink. It does not rely on having a dedicated path back to the water heater.

(Thanks for your replies thus far!

 

[ToroMorro]

Spigot in garage for washing cars?

Might be - but it's crammed right up against the body of the water heater. If that's what it was for, it'd be a tough job screwing the hose on and twisting the valve.
Thanks for the idea, though!

 

[TheEplumber]

If you have an extra pipe in the kitchen, it will be a softener loop. Locally, we plumb a dedicated hard line to kitchens and hose bibs for future softeners.
One other possibility is a trap primer line to a floor drain or a hub drain. The water supply would come from the CW at the heater

 

[ToroMorro]

If you have an extra pipe in the kitchen, it will be a softener loop. Locally, we plumb a dedicated hard line to kitchens and hose bibs for future softeners.
One other possibility is a trap primer line to a floor drain or a hub drain. The water supply would come from the CW at the heater

Thanks @TheEplumber ! No drains are nearby...but it's interesting you mention the Cold Water supply line from the heater. Hmmm...

You mention a "softener loop" - is that another term for a recirc line? I failed to mention in my original post that the CW in the kitchen is on hard water, and now what I'm hoping to do is get the kitchen CW onto a Soft Water supply (don't worry; I have RO at the kitchen sink to remove the salt).

So I'm trying to do a last bit of info-gathering here before I cut a hole in the back of my kitchen cabinet and in the sheetrock behind it. If I don't find a stubbed pipe there, my better half is going to become my bitter half...

 

[TheEplumber]

If you have softener installed, all your fixtures will be served by softener unless there is a separate line fed directly off the hard CW. I suspect that is what your 1/2" capped line is for- not a recirc line.
I plumb a dedicated line to the kitchen sink and hose bibs so I can isolate these from soft water.
Do you have an extra line at the K sink?

 

[ToroMorro]

I plumb a dedicated line to the kitchen sink and hose bibs so I can isolate these from soft water.
Do you have an extra line at the K sink?

That's exactly what I have - hard water at kitchen sink and hose bibs. Can't stand the mineral buildup on the fixture and counter anymore.
I don't know yet for sure if I have an extra line at the K sink. I seem to recall that there were 3 stubs when the wall was open before the new cabinets went in - but that was years ago.

That's why I posted the original question - my suspicion is that, since I have a stub right next to the softener, the other end of that run is in the wall behind my K sink, and I can use it for a treated/softened cold water supply.

 

[TheEplumber]

Given it's location- It could still be a recirc line....

 

[ToroMorro]

Given it's location- It could still be a recirc line....

So if it's a recirc line...it's unused at present. Wouldn't it be a dedicated run of pipe from the water heater to the furthest point away (which is my kitchen sink)?

 

[MTN REMODEL LLC]

Probly not your issue but....

We bought a retirement home in southern NV. (Now you have to understand that I discovered everything one at a time over a relatively long time...none of it made sense untill I put it altogether.)

Stub out in garage...obviously for a water supply in the garage ...no drain however.

3-way switch upstairs by the deck....did nothing I could find.

Later discovered a three way switch by the downstairs deck....did nothing I could find..

Had an electrical outlet in the garage that did not work. But then one time that I needed it , it worked.

Had a blank electrical plate way up top of the wall in the garage. I was putting in a laundry room addition and popped the plate. Electrical single gang box with the back cut out and a 1.5 inch thin wall black drainage type tube in it.

Finally, was painting the second story side deck wall (which I could not see from our deck) and noticed a blank cover plate way up high on the wall.... popped it and there was that black thin wall drainage pipe stubbed in.

?????????????????????????? Any Guesses...?????

 

[ToroMorro]

?????????????????????????? Any Guesses...?????

No clue. Other than the 3-way switch by the downstairs deck sounds like perhaps it controls the "non-working" outlet in the garage. Why anyone would have stubbed a drainage tube into electrical boxes is beyond me, unless they were planning to use it as a cheap means of electrical conduit later that they could easily fish wire through. Either way, electrical fittings and plumbing are a bad combo!

 

[ToroMorro]

Good news - I managed to locate the stub in the kitchen wall using an endoscope. Bad news is that it's not directly behind the kitchen sink cabinet. Guess I'll have to cut the outside wall, as I'm not willing to cut open so much cabinet to verify that the stub in the kitchen matches the stub in the garage.

But, thanks all for your replies - I appreciate the reinforcement of my belief that there had to be another stub somewhere!