An air admittance valve is used in applications where a VTR (vent through roof) cannot be accomplished due to construction. It is designed to open when there is a pressure change in the drainage piping system allowing a free flow of air and “preventing” a syphoning of the trap. Spring type check valves are similar and have a designated “cracking pressure” that needs to be overcome to allow the valve to operate. They are a different animal however and used typically in pressure piping. I could image that the pressure differential is very low in this application and the the AAV is sticking closed. It’s possible that the new AAV is just defective and not opening.
__________________
Truck & trailer...yes
They have many features and upgrades, more than I can list, so much, did I mention they are well equipped, I don’t know if I have enough room here....and I really don’t think you care anyway, so nope
|