Air admittance valve p trap

[Jamespf1]

Hello,

When would I use a air admittance P trap over a regular p trap in my kitchen sink?

Thanks

 

[denso13]

If you found the water was being pulled out of a normal one.

 

[Madrab]

When would I use a air admittance P trap over a regular p trap in my kitchen sink?

If your sink waste gurgles when the water empties out.

 

[Jamespf1]

just done the pipe work to the boss. And it’s a run of 8m with quite a few 45 degree turns on it.
Thinking a admittance might help with distance but wasn’t sure when it’s necessary or not.

Thanks

 

[Madrab]

To the boss on the soil stack? Certainly overly long for an unvented 40mm or 50mm pipe .... Standards are 3m @ 40mm and 4m@50mm on an unvented run.

So if you can't shorten the run by say extending a stack branch then you would ideally look to increase the size and definitely vent the run or you are in real danger of the trap getting pulled (self syphoning). Is that the only outlet on the run?

 

[Jamespf1]

Agh. Okay thanks for that information. Yes soil stack.

Washing machine as well. Okay will add vents and a inspection chamber.

I’ve done some test runs and seems to be draining okay so far

 

[dilalio]

a inspection chamber

So this run is below ground?
In 40mm?
You're asking for trouble from a sink and washing machine!
Dishwasher too?