Water Softener Drain

[Nav360]

I'm getting started on doing some plumbing to have a water softener stub out done in the garage, with the drain going into the attic. I had a few questions before I start tearing up drywall, and running PEX.

1. Is PEX-A fine for the stub out, and drain?
2. The two locations I can drain my water softener in the attic to is the washing machine drain pipe, and bathroom vent stack (picture below). Which place would be code compliant, and not cause issues later?
3. When doing the PEX-A stub out is it fine to use 90 degree fittings out of the wall or should I use a bend support?

Thanks,

 

[Reach4]

1. Stubout, maybe. Drain yes.
how big of pex were you planning for the stubouts? One inch should be good. 3/4 maybe OK. Drain 1/2 ok.
2. The washer standpipe is the only one code Complient. You should feed the softener drain thru an air gap.

3. Right angle fittings are OK. Note pex is probably stiffer than you think. So plan on having a corrugated stainless connector line between the pex and the bypass valve, or have some jogs in the pex to give a little flex.

See AG140-001 https://airgap.com/plumbing-air-gaps/

 

[Sponsor]

 

[Nav360]

1. Stubout, maybe. Drain yes.
how big of pex were you planning for the stubouts? One inch should be good. 3/4 maybe OK. Drain 1/2 ok.
2. The washer standpipe is the only one code Complient. You should feed the softener drain thru an air gap.

3. Right angle fittings are OK. Note pex is probably stiffer than you think. So plan on having a corrugated stainless connector line between the pex and the bypass valve, or have some jogs in the pex to give a little flex.

See AG140-001 https://airgap.com/plumbing-air-gaps/

I was planning on doing 1" water line, and 3/4" drain.

 

[Nav360]

Well guess a few more questions come to mind now...

1. I plan on using a check valve on the drain going into the attic since it's higher than the tank itself. Any recommendations/links to 3/4" PEX-A Check Valves? I was looking for something with PEX unions on both ends in the event I need to service it, but honestly no idea if it's not either made or check valves rarely fail.

2. I plan on using either the AG140-001 or AG140-002, which both have a 1/2" PVC slip fitting on top. What's the correct fitting to go from 3/4" PEX-A to 1/2" into the air gap? Also, any possible issues reducing the pipe size at the air gap?

 

[Reach4]

A water softener drain usually passes between 2 and 4 gpm during backwash. AG140-001 is for up to 7 gpm. https://airgap.com/product/ag140-001/

Transitioning like that would normally be done with threaded couplings. I know of no direct 1/2 PVC to 3/4 PEX couplings. There are 1/2 to 1/2 and 3/4 to 3/4 transition couplings.

https://www.supplyhouse.com/SharkBite-UIP4016-3-4-CTS-x-3-4-PVC-Sharkbite-Transition-Coupling

https://www.supplyhouse.com/SharkBite-UIP4008-1-2-CTS-x-1-2-PVC-Sharkbite-Transition-Coupling

============musing====================
OD of 1/2 inch PVC pipe is 0.840" which would also be about the ID of the coupling planned to fit over the AG140 o-ring.
ID of 3/4 inch PEX is 0.684".

Expansion 3/4 pex stretches over a barb of about 0.87 https://www.siouxchief.com/docs/def...pex---f1960-brass-fitting-system---spec-sheet

I suspect that 3/4 PEX-A, maybe with ring, could be expanded enough to fit, and then shrink. Would the force be too much for the AG140?

 

[Nav360]

A water softener drain usually passes between 2 and 4 gpm during backwash. AG140-001 is for up to 7 gpm. https://airgap.com/product/ag140-001/

Transitioning like that would normally be done with threaded couplings. I know of no direct 1/2 PVC to 3/4 PEX couplings. There are 1/2 to 1/2 and 3/4 to 3/4 transition couplings.

https://www.supplyhouse.com/SharkBite-UIP4016-3-4-CTS-x-3-4-PVC-Sharkbite-Transition-Coupling

https://www.supplyhouse.com/SharkBite-UIP4008-1-2-CTS-x-1-2-PVC-Sharkbite-Transition-Coupling

============musing====================
OD of 1/2 inch PVC pipe is 0.840" which would also be about the ID of the coupling planned to fit over the AG140 o-ring.
ID of 3/4 inch PEX is 0.684".

Expansion 3/4 pex stretches over a barb of about 0.87 https://www.siouxchief.com/docs/def...pex---f1960-brass-fitting-system---spec-sheet

I suspect that 3/4 PEX-A, maybe with ring, could be expanded enough to fit, and then shrink. Would the force be too much for the AG140?

Spent some time, and think I found some fittings that may work.

This fitting will be 3/4 MPT to 1/2 Slip PVC - https://www.lowes.com/pd/Charlotte-Pipe-3-4-IN-X-1-2-IN-SCH40-MALE-ADAPTER-REDUCING/5012476201


These two fittings are 3/4 PEX expansion to 3/4 FNPT Brass, just haven't decided if I should use the swivel or fixed version.

https://www.lowes.com/pd/SharkBite-...x-3-4-in-FNPT-Brass-Swivel-Adapter/5001460659

https://www.lowes.com/pd/SharkBite-3-4-in-PEX-A-Expansion-x-3-4-in-FNPT-Brass-Adapter/5001460625

 

[Reach4]

How do you picture the installation. Existing 2-inch standpipe box. You drill a hole in the top of the box to feed the drainage down to the air gap? You access the top of the box from the other side or some other way?

 

[Reach4]

"This fitting will be 3/4 MPT to 1/2 Slip PVC - https://www.lowes.com/pd/Charlotte-Pipe-3-4-IN-X-1-2-IN-SCH40-MALE-ADAPTER-REDUCING/5012476201 " I suspect the this is the opposite of what you want. You want the non-thread side to be 1/2.

https://www.supplyhouse.com/Spears-436-101-3-4-x-1-2-PVC-SCH-40-Male-x-Socket-Adapter[/img]

So you would want a 3/4" x 1/2" rather than a 1/2" x 3/4" OR is it the other way around???

https://www.lowes.com/pd/Homewerks-1-2-in-MIP-x-3-4-in-SOLVENT-Schedule-40-PVC-Adapter/5013090667 seems like it might be right, but you will have to check.

I am also thinking you might want a plain 1/2 coupling with a piece of 1/2 pvc pipe entering the box, and the real adapting would be outside of the box.

 

[Nav360]

How do you picture the installation. Existing 2-inch standpipe box. You drill a hole in the top of the box to feed the drainage down to the air gap? You access the top of the box from the other side or some other way?

I'll knock out the cover at the top section of box, and run the 3/4 PEX-A down to the AG140-001. I have limited access from the attic above, but that is the only way as of right now.

"This fitting will be 3/4 MPT to 1/2 Slip PVC - https://www.lowes.com/pd/Charlotte-Pipe-3-4-IN-X-1-2-IN-SCH40-MALE-ADAPTER-REDUCING/5012476201 " I suspect the this is the opposite of what you want. You want the non-thread side to be 1/2.

https://www.supplyhouse.com/Spears-436-101-3-4-x-1-2-PVC-SCH-40-Male-x-Socket-Adapter[/img]

So you would want a 3/4" x 1/2" rather than a 1/2" x 3/4" OR is it the other way around???

https://www.lowes.com/pd/Homewerks-1-2-in-MIP-x-3-4-in-SOLVENT-Schedule-40-PVC-Adapter/5013090667 seems like it might be right, but you will have to check.

I am also thinking you might want a plain 1/2 coupling with a piece of 1/2 pvc pipe entering the box, and the real adapting would be outside of the box.

It was actually the fitting I listed earlier, but I doubled checked to be sure. The variations of PVC fittings always throw me off. I just used some teflon tape on the 3/4" MPT end, and tightened the 3/4" FNPT to PEX-A brass fitting to it. (Pictured Attached)

I considered running some 1/2" PVC down to the standpipe, and making the connection in the attic with the air gap. But, due to the tight space into the box it would be impossible to get rigid pipe down into the wall. I think I'll have enough flexibility with PEX-A to run it down the wall into the top of the washer box. Just need to figure out what to do with the washer drain, as I don't think it'll fit the drain with the air gap installed. (Pictured Attached)

Measured the I.D of a 2" PVC, and doubled checked to make sure the stand pipe was also the same. For some reason it looks smaller than 2" to me, but it's the same I.D....... mind games.

 

[Nav360]

1. I plan on using a check valve on the drain going into the attic since it's higher than the tank itself. Any recommendations/links to 3/4" PEX-A Check Valves? I was looking for something with PEX unions on both ends in the event I need to service it, but honestly no idea if it's not either made or check valves rarely fail.

 

[Reach4]

Check valves normally not done for that, even if feeding both a softener and backwashing filter into the same drain line.

 

[Nav360]

Got it! Thanks for the clarification.

 

[Nav360]

Finally got around to finishing the install. Just need to do some drywall patching for the holes I had to make. All the plumbing was done using PEX-A which was fairly easy to work with. Only issue I had was a small leak on the drain elbow on the valve, but some Monster Teflon tape, and T plus 2 pipe sealant fixed the issue.

Thanks everyone for the help along the way!