A/C drawing air up sink drain.

[ice2fire]

Whenever we turn on the A/C, it's just a matter of time before the whole RV STINKS.

It appears the A/C is pulling air up the waste pipes connected to the double sink. Under one sink there is a drain pipe that connects to the drain pipe that comes down from the other sink. Under that there is a P-trap. There is also an inside vent under the sink.

Why the smell ? Sinks are used all the time, thus water always in the P-trap.

Thanks for any suggestions.

[GordonThree]

When you fill the sinks with water, and run the AC there's no smell?

AC does not create a pressure difference inside the RV, it doesn't vent air in or out, it just circulates it through a coil.

The air vent under the sink lets air into the piping not out, although it could be faulty and not doing its job.

My guess is the source of the smell is someplace else, and the air movement from the AC is stirring it up... or maybe there's something wrong with the AC itself, refrigerant leak maybe?