Odor in basement - 3 mobile techs...still not diagnosed

[CheWal]

Hello - we picked up our 2017 Pinnacle 36FBTS RL about a month ago. From the get-go there has been an odor coming up from the basement. Badly infiltrating the master bedroom from under the front side of the bed, and also coming in badly from the vent under the steps. It is not a typical septic/poop smell...it is almost like a chemical/burnt plastic smell that burns your sinuses and eyes. We have been able to stay in the unit (this is our first time as full-timers and have sold our home last month so we REALLY need help here) by leaving the front bottom panel completely off - for weeks now - so the area gets well ventilated. We have had 3 RV techs out here so far and the dealer is stumped. Troubleshooting steps taken so far -

- Formaldehyde ruled out (negative test)
- Batteries are not causing it
- Hours of sniff-testing seems to indicate it's coming from the area where the tank flush meets black tank 1 (forward tank) and where the drainage pipe exits black tank 1. Have completely sealed these fittings with gobs of RTV. Filled black tank to toilet, allowed to sit several hours - no leaks. Flush does not leak.
- More geo method / happy camper / boiling water poured into tank than you can imagine. You could drink the water that it dumps.
- The smell definitely gets worse when boiling water is dumped into black tank 1
- Ran water down the roof vent pipe, no clogs, goes straight through to black tank.
- Tech #3 is currently waiting on plumbing schematics from Jayco...is thinking there is some kind of valve actually inside the black tank and or the vent pipe (?) At this point I feel anything is possible.

So...ANY ideas? We are thinking the previous owner maybe dumped some kind of chemical down the black tank 1 that damaged the plastic and is allowing the odor to leach through the plastic, but not the water (yes, I know that defies the laws of physics but we are ready to consult a psychic here...so )


Thank you all for any advice, not matter how harebrained or crazy it sounds.

[Scottenj]

Originally Posted by CheWal

Hello - we picked up our 2017 Pinnacle 36FBTS RL about a month ago. From the get-go there has been an odor coming up from the basement. Badly infiltrating the master bedroom from under the front side of the bed, and also coming in badly from the vent under the steps. It is not a typical septic/poop smell...it is almost like a chemical/burnt plastic smell that burns your sinuses and eyes. We have been able to stay in the unit (this is our first time as full-timers and have sold our home last month so we REALLY need help here) by leaving the front bottom panel completely off - for weeks now - so the area gets well ventilated. We have had 3 RV techs out here so far and the dealer is stumped. Troubleshooting steps taken so far -

- Formaldehyde ruled out (negative test)
- Batteries are not causing it
- Hours of sniff-testing seems to indicate it's coming from the area where the tank flush meets black tank 1 (forward tank) and where the drainage pipe exits black tank 1. Have completely sealed these fittings with gobs of RTV. Filled black tank to toilet, allowed to sit several hours - no leaks. Flush does not leak.
- More geo method / happy camper / boiling water poured into tank than you can imagine. You could drink the water that it dumps.
- The smell definitely gets worse when boiling water is dumped into black tank 1
- Ran water down the roof vent pipe, no clogs, goes straight through to black tank.
- Tech #3 is currently waiting on plumbing schematics from Jayco...is thinking there is some kind of valve actually inside the black tank and or the vent pipe (?) At this point I feel anything is possible.

So...ANY ideas? We are thinking the previous owner maybe dumped some kind of chemical down the black tank 1 that damaged the plastic and is allowing the odor to leach through the plastic, but not the water (yes, I know that defies the laws of physics but we are ready to consult a psychic here...so )


Thank you all for any advice, not matter how harebrained or crazy it sounds.

It would be a lot of work but remove the black tank and see if the smell goes away.

The other comment I would make is do you know for sure your black tank ever completely drains, they often bulge at the bottom and trap things and mine was plumbed wrong and the outlet went up hill 4”. You might have something trapped in there that never comes out. If the tank is a 50 gallon under the basement, raise the front of your rig all the way while draining it. Also get underneath and push up on the Coroplast under the tank while the front is up.

[Grumpy]

You need someone to put a camera in the tank to see if anything is there.

[Mopar_Earl]

After paying 3 tech to come to you, I'd just replace the tank, plumbing and valves. Tank must be leaking fluid and/or vapors somewhere. I've heard of tank seems at the top coming open leaking odor.


Earl

[CAG]

I like Grumpy's idea. It is a cheaper trouble shooting step than removing the tank. That may come, but small steps first to solve it.

[RogerR]

How about filling all the tanks with water to see if you can find leaks at the top or somewhere in the piping.

Also, check for potential downdrafts from the stink pipes. Read once they forgot to glue them together on the way up somewhere on the forum. Smell came from inside the wall from a separated pipe.

[Shokyle1]

You stated the smell gets much worse when putting hot water in the tank. Maybe have someone on the roof when you put hot water in the tank and see if the stink is also coming from the vent which should confirm it is coming from the black tank. If it stinks I would guess you had a leak in the vent pipe. At last resort you could get a smoke machine plug the vent and pump smoke in the toilet and look for smoke leaks.

[CheWal]

I have access to one here at this campground. Great idea, Thanks.

[CheWal]

Originally Posted by CheWal

I have access to one here at this campground. Great idea, Thanks.

I was talking about dropping an endo cam down there. Thanks!

[Scottenj]

Originally Posted by CheWal

I was talking about dropping an endo cam down there. Thanks!

I put an Endo camera down mine and it wasn’t very useful, you need a sewer camera that can pivot. The tanks are long and wide but very shallow, all you will see is what is right under the toilet tube.

[Jeffur]

Heck to see if the Vent is glued into the tank.

[TaftCoach]

The smell isn't like a black tank? Going down the non poop path.

If it is burning it should stop when all power is shut off.

But my #1 guess is decomposition. Something or (Halloween hyperbole) someone died in there.

[Scottenj]

Originally Posted by Jeffur

Heck to see if the Vent is glued into the tank.

You won’t be able to see that with an Endo camera.

[norty1]

I would be back to going the smoke test route mentioned earlier.

[CheWal]

Don't think that didn't cross our minds...going down the Breaking Bad path. Prior meth lab? Dissolved body flushed down there? (sadly only half kidding...this IS Arizona - not NM, but close)

[CheWal]

Found out today it goes away when the temp drops from 80 degrees to freezing.

[Grumpy]

Originally Posted by CheWal

Found out today it goes away when the temp drops from 80 degrees to freezing.

That sounds like it is something outside the tank.

[Bayoutalker]

I am having the same thing. It gets worse as the weather gets hotter. The smell is more like a urine/ammonia smell and not at all like what comes out on a dump. I am thinking I have a crack in the tank allowing fumes to leak out. I sure hate to pull the underbelly open but that's what it's going to take.

[Still smiling]

I found a great YouTube video and used this method of black tank Cllean out and it was great. No more stink and a large amount of trapped debris came shooting out when we arrived at camp site and emptied and flushed after a long drive. It was a guy at www.trbowlin.com. He calls it bio geo
Method. If this doesn’t work I think you have a pipe leak somewhere. Good luck ��

[serge90]

A small propane leak smells like black tank.