Dishwasher causing gas leak!

[dk4dk4]

I have a double kitchen sink with the ABS dishwasher adapter tied into the horizontal pipe between the sink drains. It is after the union trap up with the sink drains.. The problem is when the dishwasher completes its drain cycle the union trap internal water seal is broken. The sewer gases are coming up through the sink drain... Perhaps too much discharge force or dishwasher is pushing air at the end of the drain cycle that breaks the internal water seal in the trap (preventing the gases from getting into the sink)? There are no water leaks in the system... If I run water from tap it re-seals the trap...

If you look at this image the dishwasher adapter is missing but mine is near the right sink drain on the horizontal 1.5" pipe... Direction is correct it shoots to the left...

I'm not sure how to resolve this issue?
Thanks in advance!

 

[CountryBumkin]

What's the point of the rubber coupler? Why don't you replace it with a solid coupler fitting? That would solve the problem.

Sorry - misunderstood. I thought you were having to repeatedly "reseal the rubber coupler" to fix the problem. I don't know where that thought came form.

 

[Sponsor]

 

[Terry]

If the trap siphons and allows the trap to dry out, that would allow sewer gas to escape into the room.
One solution to that is to add an AAV to break the siphon.

Does your plumbing go into the wall? Or come up from the floor?

 

[hj]

There is NOTHING about the drain in the photo that would let the DW drain break the trap seal, UNLESS there are other problems that the photo does NOT show.

 

[Jadnashua]

FWIW, at least in the USA, you cannot use that type of unbanded coupler above ground on plumbing...one that looks very similar, but has a metal reinforcement band around it (this keeps the pipes aligned properly) is to code. But, as HJ said, it has nothing to do with siphoning the trap dry. If there isn't a vent line in the wall, an AAV, if allowed, should solve that issue. If there IS a vent line in the wall, it may not be connected properly or is blocked, which is causing the problem.

 

[dk4dk4]

Guys the picture is not my setup, it was only for illustration. I don't have a rubber coupler (all ABS). The plumbing goes into the wall, everything is level. Each time the DW drain cycle completes we can smell sewer gas entering the room from the sink. If I run the faucet it seals the trap until the next time the dishwasher runs. I don't understand why the DW is breaking the seal on the drain cycle.

 

[Jadnashua]

If the drain line is not vented properly, your trap will siphon if you run the water through it fast enough. The vent breaks the siphon, preventing it from emptying the trap. If you drain it slowly, say from the bowl, because it is not being pumped at high velocity, it does not siphon. A properly working vent, or adding an AAV, would break the siphon, and prevent the problem.