1.5" to 1.25" Drain Reduction

Molo

Molo

Member
Messages
922
Reaction score
2
Points
18
Location
Cold New York
Hello All,

From the vertical main up to the sink drain:

Into the main 4" CI stack is 1.5" ABS. 1.5" ABS goes up into 1.25" galvanized. Galvanized forms a 90 and and goes into the kitchen sink cabinet (galv. only 6" on each side of the 90). From the galv. is 1.5" PVC up 20" to an AAV/ sante. The sante reduces to 1.25" P-trap. To sink drain stem.

1. Is there a problem with the 1.5" PVC running into the short section of 1.25" galvanized elbow, or do I need to change this galv. elbow t o1.5"?

TIA,
Molo
 
You should never reduce the size of a drain. It creates a bottleneck which causes clogged drains.
 
I know, I know, NEVER reduce the size of the drain. But when I bought all these parts 1/4" too big. I put a reducer on the galv. coming out of the bottom of the cabinet, and installed it. The galv does a quick bend in the basement and goes into about 4' of abs into the vertical below the toilet. I can fill the sink up and pull the plug and it drains fine. I can hear the AAV sucking air toward the end.

How does this installation look other than the sizing mistake?

How can you explain the good draining action? Is it the AAV?

TIA,
Molo

AAV100_0878.JPG
 
what the photo shows looks good. But you can't reduce after increasing the size to 1.5". You don't have a lot of options now. Either to redo that 1.5" part in 1.25", or to remove the galvanized (and the reducers), and run the whole drain in 1.5" since that is the size you are now at. (Use a long sweep bend). Either now or later, but later won't be nice and now is a nice time.

david
 
Here (UPC is code), the trap arm and trap of a kitchen sink have to be at least 1 1/2" tubing and the waste (starting at the santee where the AAV is) has to be at least 2"...
This is code minimum here...
 
it is a combo of `1.25 and `1.5. it drains like a beauty, like i said, a full sink drains down in a hurry, and i can hear the AAV sucking air at the end......
 
drain

The AAV "prevents" too good draining. If it were not for the AAV, you might have to hold onto everything within a foot of the drain or it would get sucked in.
 
Molo...I'm gonna hold my breath till you decide to put a 1-1/2" drain there.
It's a kitchen sink...I even rough 'em in with 2" when I'm doing new remodels because of future trouble with grease.
Yer askin' fer trouble down the road.
 
hj said:
The AAV "prevents" too good draining. If it were not for the AAV, you might have to hold onto everything within a foot of the drain or it would get sucked in.
Click to expand...


ok, it prevents siphoning?
 
aaV

That is the purpose of all vents. Without a vent, the drain speed is governed by how far the trap's outlet pipe drops before it has a source of air intake.
 
You must log in or register to reply here.

Similar threads

I
Sump pump discharge 1.25 vs 1.5 inch
Replies
10
Views
1K
Bannerman
Bannerman
D
I had a new counter and sink installed recently and I noticed that the trap was an S-trap. I am trying to replace it with a P-trap and add an AAV.
Replies
0
Views
364
David B.
D
parity_check
Fittings to use in branch with two small vertical drops
Replies
6
Views
823
Reach4
Reach4
S
Need advice: Replacing 1.5" drain pipe buried in 4" slab, pipe is tight against the bottom of slab
Replies
0
Views
2K
samuelaz
S
jessb_55
Can I cap these and add a cleanout?
Replies
8
Views
547
jessb_55
jessb_55
Back
Top