Sink Will Not Drain - Conversion of 2 Basin Stainless Kitchen Sink to 1 Basin Porcelain Kitchen Sink with Disposal

[WalterJ]

Sink Will Not Drain - Conversion of 2 Basin Stainless Kitchen Sink to 1 Basin Porcelain Kitchen Sink with Disposal.
Sink is on Peninsula and 5 feet from vent stack in wall to roof.
Before Conversion: 2 Basin Stainless Kitchen Sink, 2" PVC Exit Drain, to 2" PVC P-Trap, to PVC Adapter 2" to 1 1/2" Kitchen, to 1 1/2" Kitchen Adjustable T and Fittings, 1 Side Disposal = Drains Perfect.

After Conversion: 1 Basin Porcelain Kitchen Sink with Disposal
Attempt 1 = NO under-cabinet vertical pipe WITHOUT Air Admittance Valve,
same 2" PVC Exit Drain, to same 2" PVC P-Trap, to same PVC Adapter 2" to 1 1/2" Kitchen, to NEW 1 1/2" Kitchen Elbow and Fittings, to Disposal = NO GOOD. Backs up after 2 minutes, takes 1 hour to dissipate.

Attempt 2 = YES under-cabinet vertical pipe WITH Air Admittance Valve,
same 2" PVC Exit Drain, to same 2" PVC P-Trap, to same PVC Adapter 2" to 1 1/2" Kitchen, to SAME 1 1/2" Kitchen Adjustable T and Fittings, to Disposal and vent pipe = NO GOOD. Backs up after 2 minutes, takes 1 hour to dissipate.

What is the problem? Worked fine with 2 basins.

Called professional plumber for consultation. Said Vent Stack in wall 5 feet from drain is good and within code, no need for dangerous Air Admittance Valve. Recommended reduce to 1 1/2" Kitchen P-Trap, claiming problem was 2" PVC P-Trap was too large. Why? Hard to believe. Worked fine with 2 basins.

(yes, snaked both drain and cleanout just to be sure)

 

[WalterJ]

Yes, Porcelain Sink is a bit deeper.

 

[Twowaxhack]

You have an obstruction in the drain line.

It might be 10’ away or whatever.

I know you said you cleaned the drain. And I’m still going telling you that the pipe has an obstruction.

Could be sludge. It’ll have to be washed out,cables won’t necessarily help you with sludge unless you have some professional equipment.

 

[WalterJ]

Hi Everyone:
Part 1 - can you confirm it it is plumbed correctly.

Part 2 - can you confirm if I need a T and Vent Pipe? (I did not need one with old 2 basin sink. Vents stack is 5 feet away.)

Part 3
Hi TwoWaxHack. I will take your advice, remove all the components, stuff a garden hose in the 2" PVC drain pipe, run it and see.
Is it possible that I dislodged something into/down the drain when I changed the P-Trap and parts?

 

[Twowaxhack]

It’s piped good enough to drain. It’s not piped how I’d pipe it.
It doesn’t appear to need a studor vent, even if it does, that’s not your immediate problem.


Buy one of these, screw it onto a good quality garden hose. Shove it into the cleanout a couple feet. Turn water on. Have someone help you control the water on/off while you make sure nothings flooding.

https://www.homedepot.com/p/Husky-M...pip_alternatives-_-301879467-_-301879205-_-N&

 

[Twowaxhack]

To pipe it I would use one of these straight out of the disposal looking straight down into a ptrap exactly like you have now. Oatey 1-1/2 in. x 4-3/4 in. Black ABS Garbage Disposal Tailpiece-HDC2670 - The Home Depot

To accomplish this you would need to cut the pipe where it enters the 45. Cut it as close to the fitting hub as possible. This will give you pipe to install a 2” pvc coupling onto the pipe. Clean all paint from the pipe you cut.

It must be cut straight. Then add your coupling.

Your 2” ptrap will have an inlet. You need to install a 2x1.5” reducing bushing into the inlet. The glue a 1.5” male pvc trap adapter into the bushing. It’ll have threads on one side and 1.5” pvc pipe size on the other, male spigot.

Slide the trap adapter nut up onto your new garbage disposal tailpiece I linked above.

Slide the trap up and screw the nut down to snug it up. You may need to trim off the tailpiece if it’s too long.

Now with the trap attached to the disposal and your coupling on the pipe at the wall, swing your trap to line up as straight as possible to your coupling.

Screw the trap outlet onto the trap. Line it up with your coupling.

Use a tape measure to measure to the face of each hub, trap outlet to the coupling face. Add 1.5” to this measurement to allow pipe to enter the hubs. You’ll use 2” pipe.

You can also rotate the disposal to help you line the ptrap up as straight as possible.

 

[MicEd69]

Twowaxhack's suggestion would provide a much cleaner and efficient installation and would be worth changing your system regardless of what the draining issue is.

But just a few questions, and I'm not trying to be condescending here.

1. From your pictures, I'm assume the disposal is new. When you try to drain the sink, have you been running the disposal? Could the disposal be blocked with plastic or packing material from the box?​

2. Have you checked that the disposal tailpiece connection to the disposal isn't blocked by some plastic, some packing material or if the gasket is incorrect or not cut properly?​

3. As Twowaxhack said in his installation recommendation, "You may need to trim off the tailpiece if it’s too long." I assume you did that to your tailpieces if it was necessary in your current installation. Sometimes people think that tailpiece should be extended as deep as possible into the receiving piece to prevent leaks which actually plugs the end of the tailpiece against the backside of the elbow or tee.​

4. Sometime people also put a wad of paper towels or a rag in the drain line during installation to keep sewer gases from smelling up the kitchen. If all or some of those aren't removed, they will travel down the drain line and can easily cause a blockage.​

5. Are there any other fixtures that are flowing into that drain line downstream from the vent stack in the wall? If so, are they draining well.​

 

[WalterJ]

Hi Guys - Still Have Exceptional Low Drain Flow in Kitchen.
Current Conclusion: For Some Strange Reason, Drain Became Blocked at the same time sink change unrelated!?!?!

Facts Review:
Conversion of 2 Basin Shallow Stainless with disposal to 1 Basin Deep Ceramic with disposal. (ground level of house)
All was working fine with 2 Basin Sink.
Again, all the 2" is/was existing. I did not add any 2".
Sink is on Peninsula, Vent Stack is 5 feet from Sink.
Vent Stack is a vertical 90 degree T up, and I believe the drain goes 90 degree down at T to get to below floor level.
Water can run for about 45-90 seconds, then backs up.

Efforts:
1. Removed T and plumbed disposal directly to 2" P-Trap. - no good/change.
2. Put T back and added Vent Stack in cabinet. no good/change.
3. Removed all 1 1/2 pipes, ran Home Coil Spring Snake in 2" drain to vent T (5feet). - no good/change.
3. Home Coil Spring Snake in Adjacent 2" Clean Out (8feet on a different angel). - no good/change.
4. Called and Paid Radiant Plumbing Service. They advised that all 2" pipe and P-Trap be changed to 1 1/2 kitchen pipe (I do not buy this theory).
5. Removed all 1 1/2 pipes, ran garden hose into 2" drain. BINGO, Water can run for about 45-90 seconds, then backs up. PROBLEM IS NOT SINK, DISPOSAL, P-Trap, Pipe Size, or Reducer.
6. Removed all 1 1/2 pipes, rented and ran Commercial Coil Spring Snake in 2" drain to (33feet, which would take it 6 feet past front door)(or up the vent stack . - no good/change.
7. Purchased Drain Bladder 1-2" version. was able to stuff in 2" drain only to vent T (5feet). - no good/change. (it did not hold back the water, got backflow under the sink after 45 seconds.)
8. Put garden hose into other sink drain on ground level (powder). Drains fine. Conclude Kitchen Sink clog is before where Powder Sink joins Kitchen Sink drain.

All Variables or potential causes. (starting from user perspective downward):

• Rubber Splash Guard - nope, removed.
• Disposal - nope, removed.
• Disposal and bottom of sink is now 5" lower than before leaving only 1-2" of downward run to drain - nope, removed.
• P-Trap - nope, removed.
• Anything I did - nope, removed.
• Venting - nope, same as before.
• 33 feet drain coil snaked - no improvement. (possible that snake went UP T to vent and not down T drain to below floor level)
• 5 feet drain bladder - no improvement.
• All other plumbing in house fine.

 

[Twowaxhack]

Find the vent, cut it open and shove the drain bladder as far down as you can.

If you need to cut a wall open to do that then so be it.

It has to seal and pressurize to do its job.

Run the cable 50’ into the drain.

 

[WalterJ]

SOLVED-RESOLVED!
Hired pro plumber.
Yes, there are 3 90 elbows. Yes, your snake was likely going up the vent.
He had scope and we could see clog about 15-20'.
Because of the elbows, his large snake and powerful tools would not make it after 3 attempts and different heads.
Solution: Cut off all extra 2" fittings for better access, used my thinner "home" snake, Success.
Conclusion: the drop in temperature of pipe and slab and blob was a coincidence to my plumbing project.
Topic Closed - thank you all.