Gray Tank Smell (Seriously annoying)

[Wulrich]

I love our travel trailer, but we have been having some serious issues with a very potent smell.

Issue: Every time we run the kitchen faucet we get a rotten egg smell out of both of our A/C units almost instantly. We’ve had the unit for about 3 months, and this has been going on for about 2 months.

Things I’ve tried:

1) Replaced the air admittance valves underneath both sinks.
2) Got on top of the unit to ensure the vents weren’t clogged, even ran water down them.
3) Cleaned gray tank, put tons of detergent, fragrances, and cleaning solutions in the gray tank to clean it.
4) Checked the anorod on the water heater
5) Keep the gray tank closed until ready to empty
6) Called the manufacture, they sent out a tech and were unable to find the problem. Have also called multiple service techs and no one seems to have heard of the issue.

Does anyone else have any other ideas? We are seriously bummed about it, my wife and kids hate it. We love the unit except for this issue. Any help is appreciated!

I have a 2022 Forest River Travel Trailer, Heritage Glen

[opnspaces]

Quick warning on the dry ice. It can give you frost bite if you touch it with bare hands. Wear some kind of gloves thicker than surgical gloves or use a pair of tongs to pick up the ice pieces.

[jjrbus]

Tough one!! If all else fails a plumbing smoke test can be performed, either diy or professionally. Google RV plumbing smoke test. I had to strip a wall to repair a screw hole in the vent pipe.

[midnightsadie]

had a smell one time was the seal around the commode. the rubber one at the slide gate.

[Wulrich]

2112 wrote:
Don't forget to let us know the cause when you find it. Inquiring minds what to know.

I definitely will!

[2112]

Don't forget to let us know the cause when you find it. Inquiring minds what to know.

[Wulrich]

JimK-NY wrote:
Do I understand there are no odors unless the A/C is running? If that is the case, I don't see any connection with the grey water. I would check the A/C. Maybe a dead critter in the unit. As mentioned the A/C does not pull any outside air so the offending item would be inside in the A/C or ductwork if there is any.

No odors unless the A/C is running. The A/C smells perfectly fine unless I’m running the kitchen faucet, so it’s hard to believe that there is something inside the unit that is making it stink. But I will check

[Wulrich]

opnspaces wrote:

Wulrich wrote:

Issue: Every time we run the kitchen faucet we get a rotten egg smell out of both of our A/C units almost instantly. We’ve had the unit for about 3 months, and this has been going on for about 2 months.

Has the gray tank ever been removed? It sounds like there is a break or separation high up in the vent pipe. What I would do. First drain the gray tank so there is lots of air in the tank. Climb up on the roof with a bottle of Pine Sol and a roll of duct tape. Take the cover off the vent pipe and make sure it sticks up out of the roof and the pipe is sealed all the way around the exterior. If it is not sealed or doesn't stick up you have a potential problem.

Carefully pour about a cup of pine sol down the vent pipe but do not splash it outside the pipe. Now slap a piece of duct tape over the end of the pipe to seal it off.

Go down and start the AC and then run the kitchen sink. Does the smell come out? If it still smells shut everything off and remove the air admittance valve and slap a piece of tape over the end of the pipe. Repeat the test again. Does it still smell?

Alternatively. Leave the tank with a bunch of water in it. Go to a place that sells dry ice (in my area a few grocery stores and Baskin Robins ice cream stores sell it) Buy about 2 pounds, leave the dry ice wrapped up and take it up on the roof in a dry bucket and a hammer. Break up the ice into smaller chunks with the hammer and drop it all down the vent pipe. Give it a minute or two to really start melting and then go turn on the AC and sink. Hopefully you can see the vapor from the ice escaping where the stink is coming out.

Do you have or know anybody who has a Halloween smoke machine? Maybe you can rig it up with a 10 foot hose and run the hose down the vent pipe and into the gray tank. Now fill the tank with fog. Wait a few minutes and test for leaks.

Let me try all of these this weekend, those are good ideas. I called the company that makes my air admittance valves and they are sending free replacements as well.

[JimK-NY]

Do I understand there are no odors unless the A/C is running? If that is the case, I don't see any connection with the grey water. I would check the A/C. Maybe a dead critter in the unit. As mentioned the A/C does not pull any outside air so the offending item would be inside in the A/C or ductwork if there is any.

[opnspaces]

Wulrich wrote:

Issue: Every time we run the kitchen faucet we get a rotten egg smell out of both of our A/C units almost instantly. We’ve had the unit for about 3 months, and this has been going on for about 2 months.

Has the gray tank ever been removed? It sounds like there is a break or separation high up in the vent pipe. What I would do. First drain the gray tank so there is lots of air in the tank. Climb up on the roof with a bottle of Pine Sol and a roll of duct tape. Take the cover off the vent pipe and make sure it sticks up out of the roof and the pipe is sealed all the way around the exterior. If it is not sealed or doesn't stick up you have a potential problem.

Carefully pour about a cup of pine sol down the vent pipe but do not splash it outside the pipe. Now slap a piece of duct tape over the end of the pipe to seal it off.

Go down and start the AC and then run the kitchen sink. Does the smell come out? If it still smells shut everything off and remove the air admittance valve and slap a piece of tape over the end of the pipe. Repeat the test again. Does it still smell?

Alternatively. Leave the tank with a bunch of water in it. Go to a place that sells dry ice (in my area a few grocery stores and Baskin Robins ice cream stores sell it) Buy about 2 pounds, leave the dry ice wrapped up and take it up on the roof in a dry bucket and a hammer. Break up the ice into smaller chunks with the hammer and drop it all down the vent pipe. Give it a minute or two to really start melting and then go turn on the AC and sink. Hopefully you can see the vapor from the ice escaping where the stink is coming out.

Do you have or know anybody who has a Halloween smoke machine? Maybe you can rig it up with a 10 foot hose and run the hose down the vent pipe and into the gray tank. Now fill the tank with fog. Wait a few minutes and test for leaks.

[Lantley]

Dave in TN wrote:
This product worked for me when we encountered grey tank odor issues. Of course if your problem isn't tank related this wouldn't help.

https://www.amazon.com/Camco-40597-Black-Cyclone-Plumbing/dp/B00SQ1K19A?th=1

These^^^ are fancy vent caps. As I initially mentioned the vent caps are a potential solution. I had a similar issue and resolved it with
cyclone vent caps shown above.I think without the proper cap the odor lingers at the roof line, maybe it even infiltrates below the roof line and into the attic space. Running the A/C circulates this foul air into the living space and you notice/smell the problem. Check your roof vents!

[Wulrich]

ernie1 wrote:
Make doubly sure the traps under your sinks have enough water in them to form a seal that will not allow sewer gases back into the coach. I had that problem in the past where after traveling for a bit of time or after having just dumped the gray tank waste which might siphon out the trap, I would get a foul odor from the gray water tank. Nowadays, I try to remember to screw down tightly the sink drain plug which prevents the loss of liquid in the trap.

I’ve checked the p-traps, they were good.

And I don’t get the smell if the ac’s are off at all.

[agesilaus]

bukhrn wrote:
You mentioned that you get the smell with the AC running, do you get the same smell from the sink area Without
the AC on?

Not as noticeable, but it is there.

[JimK-NY]

I had a similar issue many years ago except it had nothing to do with the A/C. Traps seemed Ok with water in them but the stench from the gray water tank was intense. Two steps have helped to minimize/eliminate the problem. First we got fine mesh stainless steel traps for the kitchen sink. That helps to keep all but small food particles out of the gray water. Next I bleach the tank fairly frequently. I add about a cup of bleach to the tank every few weeks. I have even rinsed out the tank by first filling the tank with a hose and then letting it empty completely.

[Latner]

ernie1 wrote:
Make doubly sure the traps under your sinks have enough water in them to form a seal that will not allow sewer gases back into the coach. I had that problem in the past where after traveling for a bit of time or after having just dumped the gray tank waste which might siphon out the trap, I would get a foul odor from the gray water tank. Nowadays, I try to remember to screw down tightly the sink drain plug which prevents the loss of liquid in the trap.

X2 I always run water into the traps for this reason.

[ernie1]

Make doubly sure the traps under your sinks have enough water in them to form a seal that will not allow sewer gases back into the coach. I had that problem in the past where after traveling for a bit of time or after having just dumped the gray tank waste which might siphon out the trap, I would get a foul odor from the gray water tank. Nowadays, I try to remember to screw down tightly the sink drain plug which prevents the loss of liquid in the trap.