Air Admittance Valve

Hi there,



First time posting so please go easy,



I have just replaced my AAV, as for the last few days i have been getting an awful smell in the bathroom.



I have installed the new valve which is a Floplast AF push fit AAV. But i can feel a draft coming from the vent Surely this isn't right, and what can be causing it?



Please ignore the pipe work, not my handy work and will soon be getting replaced. Also the black collar you can see is where i have cut off the old solvent weld AAV.

 

It seems the draft is coming from the vent