Mechanical Air Admittance Vent Plumbing- HELP HELP

[jbcom41]

Hi All

Can someone please, please put an end to my pain... my father in-law has fitted 2 Mechanical Air admittance Vents to our system and the toilet still rises when you flush and the system still pulls.... please see image below... can someone please HELP...

 

[Dotty]

You've got a partial blockage.

 

[ShaunCorbs]

as above and why has he fitted 2?

 

[snowhead]

As above ,, Blockage.

And you've drawn the arrows the wrong way around.
Air admittance valves allow air IN not out.

 

[jbcom41]

He thought that the first one was not enough (100mm) so he added anther one... if we leave the Vent off the second one, everything flushes ok, the system works ok, but as soon as you add the vent, the toilet rises and the system pulls...

 

[Dotty]

Blockage........

 

[plumben]

I'd vote for a blockage somewhere or partial

 

[snowhead]

He thought that the first one was not enough (100mm) so he added anther one... if we leave the Vent off the second one, everything flushes ok, the system works ok, but as soon as you add the vent, the toilet rises and the system pulls...

NO, the system doesn't work OK with the vent off.
The water is backing up in the stack and running away slowly.
The mising AA-vent allows the air pressure out the system hence the water in the WC not lifting.

Take a vent off, cover the hole with cling film and flush a toilet.
The cling film will balloon up.
If it was mimicking an AA-v it should be sucked in.

I've seen AAV's confuse Drain unblocking Professionals

 

[Rickster123]

Blockage........

Or........

 

[Dotty]

Blockage........

Or........

Block. Age.

 

[ShaunCorbs]

Or........

dead rat