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Author Topic: Grey water emptying issues  (Read 376 times)

roaminrebelles

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Grey water emptying issues
« on: July 26, 2020, 04:57:14 PM »
So my grey water meter says my grey water tank is full, Im hooked up at the rv park, pull the grey water valve and hear whooshing. Tank still says full, figure Id give it some time to reset and check later. Tomorrow, horrible smell coming from bathroom sink while doing dishes in the kitchen, upon inspection is slow to drain. Check meter and grey tank still says full. Pull the valve again and hear water, not a lot but some. Meter still says full after this. Any ideas?

Lou Schneider

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Re: Grey water emptying issues
« Reply #1 on: July 26, 2020, 05:24:27 PM »
Tank level meters are notoriously unreliable - they're just a pair of screws at each level that lets current flow between them when they're wet.  It's easy for crud to hang up on them and create a bridge after the tank is drained.

Tank odors can come up through the P-trap under the sink.  Normally the trap stays full of water and creates a block against sewer gas coming up into the sink.  When you dump the tank water can exit faster than the tank vent can replace it with air and the resulting vacuum sucks the water out of the sink traps.  Pour a cup or two of water down each sink after you dump to refill it's trap.

« Last Edit: July 26, 2020, 05:28:11 PM by Lou Schneider »

Rene T

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Re: Grey water emptying issues
« Reply #2 on: July 26, 2020, 05:35:37 PM »
When you dump the tank water can exit faster than the tank vent can replace it with air and the resulting vacuum sucks the water out of the sink traps.  Pour a cup or two of water down each sink after you dump to refill it's trap.

To prevent that they should have installed a air admittance valve under the bathroom sink. If the valve is stuck closed, it could suck the water out of your trap when you drain the tank.  Look under your sink and you may see a vertical  pipe. On the end of the pipe will be the valve. Reach up und unscrew it it from the pipe. You may have to replace it. Theyre not expensive.
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ChasA

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Re: Grey water emptying issues
« Reply #3 on: July 26, 2020, 06:22:17 PM »
Belles, many rvs have 2 gray tanks. I suspect this is your situation.  I would get under the RV and look around. I've read on this forum that some manufacturers do a great job of hiding a second dump location.
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SpencerPJ

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Re: Grey water emptying issues
« Reply #4 on: July 27, 2020, 07:10:01 AM »
My guess 2 gray tanks also.  You should put your RV model and year in your signature so that we have a glue as into what you have and can help give you ideas.
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roaminrebelles

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Re: Grey water emptying issues
« Reply #5 on: July 28, 2020, 02:50:47 PM »
Thank you all so much, that is incredibly helpful!