Hi,

I have a new installation in a studio apartment.

The toilet sits on a 3" drain pipe. 12" away (on the other side of the wall) is the kitchen sink with a studor valve. There is a 2" pipe from kitchen to 3" stack.

With the studor valve in place, when I flush the toilet, it flushes slowly, then a couple of air bubble pop up. If I place the valve on top of the kitchen pipe (instead of screwing it in), it pops off, indicating pressure instead of suction.

When I remove the studor valve, the toilet flushes normally.

I have tried 3 different studor valves.

Any ideas?

Thanks.

it pops off, indicating pressure instead of suction.
That indicates a partial blockage in the toilet line. Pull toilet and snake the line.

That indicates a partial blockage in the toilet line. Pull toilet and snake the line.Could be, but it's a new installation. 3" pipe and all other pipes are new, never used. Nothing has gone down the toilet except water.

How many times can you flush the toilet without the studor vent in place? 3, 4, 10 times?

If you can flush the toilet repeatedly without the studor vent in place then even if you tried 3 studor vents they must all be defective. Sounds ridiculous to me, too, but only thing that makes sense here.

Back to you...

Mark

3" pipe and all other pipes are new, never used

OK, but the water going down the toilet drain is pushing air back up the pipe. That is why the Studor vent is being blown off the pipe. If drain line is clear all the way to the sewer main the air would not be pushed back up the pipe.