Stinks right after dumping

[Woodchopper]

Originally Posted by dennis45

As others have pointed out, leaving the gray tank open is not recommended. These tanks are holding tanks and not designed for flow through operation like your sinks at home. By leaving the Grey tank open, you allow solids to accumulate on the bottom of the tank and over time, will result in a foul smell. Both the black and grey tanks should be at least half full or better before dumping.

AND leaving the grey dump valve open while connected to a campground sewer system allows the stink from the sewer system onto the drain system of your coach.... as well as "sewer flies", (aka: "drain flies"), if they are in the campground sewer.

Believe me you do not want sewer flies in either of your tanks...see: How to Get Rid of Drain Flies: 14 Steps (with Pictures) - wikiHow

[garbonz]

Originally Posted by Indy54

I'm not dumping the gray tank. It's always open. I just close it when I dump the black. Then open it right back up

Don't do that anymore

[garbonz]

Originally Posted by Indy54

You mean. The sink maybe drained into the black tank?

I am wondering about that also. If it is easier for the mfg to route the bath sink into the black they may do that. Time to chase that plumbing.. p trap should still be working unless the vent line is plugged.

[marjoa]

Originally Posted by Indy54

It seems that if I dump the tank with any fantastic fan on in the coach, the problem is worse.

Don't run fan.

[dave&ginny]

Check under both of your sinks. Many RVs use "mechanical Vents" instead of pee-traps. When these traps go bad they allow odors to come into the coach. A lot of times, the smell can come up through the washing machine drain.

As others have already said, don't keep you tank drains open

[curtsr]

Originally Posted by PanJH

Do you have a black tank flush ? If you do and it was installed by the factory, there is likely an anti-siphon/vacuum breaker valve on that line. On our coach, the valve is in the vanity and on occasion, it has malfunctioned and let in smell. I just purchased a brass Watts valve to replace the cheap plastic one.

+1 we had a 36la that had a bad anti siphon valve that stunk up the coach every time I dumped the black tank, replaced it with brass valve all is good now.

[Indy54]

Originally Posted by curtsr

+1 we had a 36la that had a bad anti siphon valve that stunk up the coach every time I dumped the black tank, replaced it with brass valve all is good now.

Appreciate the responses. I have replaced all 3 air admittance valves for grins. Each time this has happened, the smell does NOT come from under the half bath sink where the anti-siphon valve is, but I'll swap this out anyway as it does look pretty cheap. The last couple times I've dumped the black tank, I've left the gray valve shut and have not had any issues..

[MisterT]

if you think about it, leaving any tank valve open provides an easy way for sewer smells to re enter your coach plumbing system, and ultimately into the coach, even if it's the gray tank valve - the last thing you dumped was the black tank, so THAT is the smell you will have come back thru the gray tank since you've now reopened it to the open sewer system - any sink or shower that is without a p-trap(and with water) could be the culprit that allows it back in...

[Brockx]

Close your kitchen and wash basin (use the stoppers you normally use), buy a flat stopper to lay over your shower drain, when you drop the tanks. This is good practice when travelling also.

[lonfu]

What???? are you saying your poop stinks???? I'd never admit to that

I'm assuming you have a factory black water flush system installed on your coach. Typically there is a check valve for your flush system installed under your bathroom sink that keeps the water from your black tank back flowing into your fresh water supply. It vents directly into the inside of the coach to allow air to enter the line when you dump your tank. Sounds like you may need to replace it. they usually look something like this but can be metal, black or clear plastic like this one.

http://www.etrailer.com/Accessories-...FUdufgodWZMKjw

When they fail they allow black tank fumes to enter the interior of the coach.

The other thing is toilets have an internal vapor check valve, should this valve malfunction it too will allow fumes in. This non rebuildable valve is the primary reason why toilets get replaced. Both plastic and ceramic toilets have these non rebuildable valves. Typically you get about 10 years of use out of them before they need to be replaced.

Sounds like you are dumping correctly to me.

[lonfu]

When dumping your black water, even when hooked up full time at an rv park, you must close the gray water to prevent draining your p-traps and filling your coach with septic gas.

[PanJH]

Originally Posted by lonfu

When dumping your black water, even when hooked up full time at an rv park, you must close the gray water to prevent draining your p-traps and filling your coach with septic gas.

Not sure how draining the black tank would effect the p-traps on the gray side ??.