Black Holding Tank slow to drain...
Our Black Holding Tank is slow to drain. Can this be caused by a bad Air Admittance Valve or a clogged vent cap or both? The tank dumps fine at first, but it eventually backs up and then very slowly...
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Mine did that. Until I was dumping one time and a plastic circle came out.
When they cut the hole for the toilet and/or the drain, the plastic fell into the tank and they left it there. It was partially obstructing the drain when nearly empty.
Finally, after about 2 years, it hit just right and came out. Luckily, I was at home using a Flojet macerator with a clear section above it. It trapped in the clear section, so I KNEW what it was. I never had a slow drain again.
When they cut the hole for the toilet and/or the drain, the plastic fell into the tank and they left it there. It was partially obstructing the drain when nearly empty.
Finally, after about 2 years, it hit just right and came out. Luckily, I was at home using a Flojet macerator with a clear section above it. It trapped in the clear section, so I KNEW what it was. I never had a slow drain again.
