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Air handler condensate P-trap installation

user-7061227 | Posted in Building Code Questions on

I have three air handlers in my conditioned attic for my Mitsubishi ducted mini split condenser. Today, I found all three condensate P traps installed askew as shown in the picture. I am concerned they will not function properly. Any thoughts would be appreciated.

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  1. Expert Member
    BILL WICHERS | | #1

    That won’t work.

    Assuming I’m seeing that pic in the correct orientation (sometimes pics get rotated when posted), the trap is sideways. The trap works to prevent gases from getting through the pipe by holding some water in the trap to make a seal against the passage of low pressure gas. If the trap is oriented so that it won’t hold some water in the “U” shaped part, then it isn’t working as a trap — it’s just a curved piece of pipe.


  2. bennettg | | #2

    I think the pic should be rotated 90d. clockwise. Regardless, not a good install. I'm guessing the installer cocked it to get the drain line back under the AH. That's a Rectorseal EZ trap. It should be installed level with the "U" legs vertical. I think it should be re-plumbed with the trap oriented properly and so you can get to the caps to clean it out, particularly if you're in a warm-humid location. That vertical stub is in the secondary drain. My AH has an overflow switch there. I'd put a plug on it so it doesn't suck air or install a switch.

  3. user-7061227 | | #3

    Which overflow cutoff switch would you recommend on the secondary drain stub?

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