Air admittance valve fitting below toilet,

Discussion in 'Plumbers' Talk' started by Jackie Ng, Jun 24, 2022.

  1. Jackie Ng

    Jackie Ng New Member

    Hi,

    I am installing a new en-suite toilet upstairs in a new location , the soil stack is installed by my builder going downstairs directly and into the ground where the main sewers are. He’s installed the air admittance valve on the floor below , which is slightly below where the toilet is.

    I asked the plumber if it’s ok as it’s below the toilet , he said yes, but most places I read online saying it needs to be above a certain level.

    Can anyone help me please , as the plumbers insisted it’s ok.
     
  2. Sjr120

    Sjr120 Member

    It needs to be above the highest spill over point of the sanitaryware that drains into the pipe - so either above the rim of the toilet pan or if a basin also drains into it then it must go above height of the top of the basin.
    Unless regs have changed recently that is!
     
    Cliff Rees and CGN like this.
  3. Cliff Rees and jimbobby like this.
  4. Sjr120

    Sjr120 Member

    Ah, okay. Must read more!
     
  5. Jackie Ng

    Jackie Ng New Member

    82621BA9-5714-4700-A332-495E97B1FFBB.jpeg 82621BA9-5714-4700-A332-495E97B1FFBB.jpeg
    Thanks , I understand the regs require this , obviously my builders are not following it , and unwilling to do it another way coz it requires more work

    my concern is whether if the physics will work , that is the valve installed below the toilet level , it’s in the garage , which the soil pipe runs to the ground. Will it cause smell to be released or blockages ?
    2F95AC7A-8611-4C70-9D25-CF7C5CD264A8.jpeg
    82621BA9-5714-4700-A332-495E97B1FFBB.jpeg
    thanks
     
    Last edited: Jun 24, 2022
  6. AnotherTopJob

    AnotherTopJob Screwfix Select

    I think the only reason for the height requirement is so that in the event of a blockage, any overflow would be highly evident by running into a basin/toilet etc.

    If an AAV is below the spill level, then an overflow could result in a leak from the valve first, which if boxed in will not be seen, and likely to cause a lot of damage.

    I assume AAVs that can be fitted at any level won't leak.
     

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