plumbing problem at work

[capz]

We have a situation at work where we had to remove a commercial disposal and cut piping away from a sink drain. Now we're left with the u-shaped trap 2 feet from the bottom of the sink. The problem is the sink now has a 7'' hole so we can't just put a new drain in. And we can't seem to find a reducing collar. So I used heavy plastic with a drain hole and pvc as a reducer. I'm using 2'' rubber hose just slipped in the trap, unsealed as the drain. The problem is it won't drain. It comes back up through the hole at the top of the trap.I thought gravity would allow this to work. All the drainage is well below the sink. I think it's a partial blockage further down the piping. Another co-worker thinks it can't work that way. Can anyone shed some light before we bring in a plumber?

The reason we're taking a temporary approach is we're remodeling in 6 mos. and a new sink and disposal is $1500, which we won't need down the line anyway.

 

[sprink56]

We have a situation at work where we had to remove a commercial disposal and cut piping away from a sink drain. Now we're left with the u-shaped trap 2 feet from the bottom of the sink. The problem is the sink now has a 7'' hole so we can't just put a new drain in. And we can't seem to find a reducing collar. So I used heavy plastic with a drain hole and pvc as a reducer. I'm using 2'' rubber hose just slipped in the trap, unsealed as the drain. The problem is it won't drain. It comes back up through the hole at the top of the trap.I thought gravity would allow this to work. All the drainage is well below the sink. I think it's a partial blockage further down the piping. Another co-worker thinks it can't work that way. Can anyone shed some light before we bring in a plumber?

The reason we're taking a temporary approach is we're remodeling in 6 mos. and a new sink and disposal is $1500, which we won't need down the line anyway.

I think I have this picture but is the water comming back up into the sink or thru a hole in the trap:huh:.

In any case if it is backing up into the sink you have a blockager downstream. You may be able to blast it out with one of those expandable pusating gizmos on the end of a garden hose. You wil need to insert it into the hard pie at the trap because it will blow that hose off. Also..you need to seal that hose off at the trap or it will leak out at that point. You have to generate enough head pressure to push the water thru the trap. If there is a leak where the rubber hose slips into the trap...thats where the water will go. Good Luck.

 

[capz]

Thanks for the response and help.
The trap is cut off at a mating point about 4'' above the U. It's at this point the water is flowing back out. The hose end is just pushed in there. There might be a blockage as we've had problems before with the line this drain goes into. Assuming there is no blockage, shouldn't the loose hose in the trap work ok, as gravity is the same 4'' above the trap as it is 2 feet above in the sink? Or is it normal for water to back up a few inches above a trap?