How to connect air conditioning condensate drainage to vanity?

[PeterHat]

I have a new build and there is a smell coming from the bathroom vanity.  When I look at how the A/c Condensate drainage is connected to the waste from the basin there is air gap as I believe is required.  Though as it is connected after the P trap there is now an opening which I believe is the cause of the problem.  Is the way it has been connected legal or appropriate.  See photo for details

[Dave-1]

Afternoon @PeterHat 

Now that is an interesting hook up. I suspect it isnt the correct way and can see a bunch of future issues down the track if the pipe backs up. 

If its a recent install I would get them to come back and explain why they think its legal (It could be ???)

If its too far past I would seal around the joint with some compound type tape.

 Self-Amalgamating Tape, EPR (Ethylene Propylene Rubber), 19 mm x 10 m 

It bonds to itself, and I have used it on radiator hose to get me out of trouble for a few days.

Dave

[EricL]

Hello @PeterHat 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your aircon drain.

The drain connection technically should be done after the trap and not before it. What's happening now is that the sewer gasses are passing through the open "T" section and polluting the air in your bathroom. If the drain was installed after the trap all the foul air would be stopped by the trap and natural draining would occur. I recommend getting another plumber to get a second opinion on the matter.  

If you need further assistance, please let us know.

Eric