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Old 09-27-2016, 05:47 PM   #1
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Angry Black tank odor


I have a 2004 Fleetwood Discovery 39 L. I am having a problem with black tank odor when I use the fan in the restroom. There must be something
not working properly in the coach to cause that problem. Where is it located and what is it called and how to replace it.


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Old 09-27-2016, 05:54 PM   #2
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Few questions:

Are you keeping water in the bowl and does it stay or leak out?

Is it doing it all the time or just at certain times?

Are you flushing the tank regularly? and are you using tank chem?

The toilet in a RV is more like a porta-potty then a house toilet. In an RV it just drops straight down into the dark tank, it does not have a P-trap. So if the bowl water is not staying the rubber on the stopper is not sealing and will cause the odor.

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Old 09-27-2016, 06:24 PM   #3
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You also NEVER want to have the bath fan running when you flush. you're just drawing the odors up through the open valve. Shut off the fan, flush, let the bowl fill w/water & if there are lingering odors, only THEN turn on the fan.

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Old 09-27-2016, 07:30 PM   #4
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Not sure when you are running the fan, but as stated above don't do it while flushing. I have also found TankTech keeps the odor to a minimum as opposed to the perfume chemicals.
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Old 09-27-2016, 08:10 PM   #5
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and always start with 3-5 gallons of water depending on your capacity may be more.. so solids drop below water level..
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Old 09-27-2016, 08:53 PM   #6
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I had the same issue and learned not to turn the fan on when flushing the toilet as the fan was sucking the odors out of the tank. I also make sure there is plenty of water in bowl before use as that cuts down odors in the bathroom.
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Old 09-27-2016, 11:18 PM   #7
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There are a couple of other possibilities: 1) black water vent is blocked - may be fixed by passing a hose through the vent from the roof and gently irrigating the vent, and 2) there may be an 'air admittance valve' defect below the sink - basically a vent that sits on a upright pipe that can be clogged and needs to be removed and flushed - or replaced ... can emit the same odor as a black water tank though its connected to the grey water tank (I think the grey water tank smells worse than the black water tank over time) ...
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Old 09-28-2016, 01:46 AM   #8
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Ditto air admitance valve, ours failed recently and what a smell with fan on, all sweet now.

As to fan on when flushing, well common sence to me but DW required instruction!
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Old 09-29-2016, 05:07 AM   #9
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Our MH is piped for a washer/dryer but we elected not to have the w/d. Pipe was not capped, once the trap dried out the smell started. We capped it.
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Old 09-30-2016, 06:49 AM   #10
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If you have checked all of the previous suggestions and still getting some odor, replace the seal between the toilet and the floor flange. The fan could pull air in that way too. Might also think about sealing around the toilet base itself with some caulking. Whatever it takes to prevent air from being pulled from the black tank area.

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black tank, odor, tank

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