Black Tank Smell.

[fishn2dmax]

I have an 08 2900 MK and would like some suggestions or assistance to an on-going problem ( since new) with black tank smell / gases seeping into the bathroom area. The problem has been acknowledged by the dealer and worked on by my dealer with no obvious/ easy solution found. The toilet doesn't appear to leaking and the bowl holds water. However, if there is any amount of waste or just chemical in the black tank, the smell is very, very STRONG in the bathroom & coach ( waste or chemical) when the coach is moved slightly or bounced (traveling).

The black tank roof top tank vent cap was checked for obstructions, and the seal around the base of the toilet doesn't appear to be leaking? The smell ( black tank gases) smell like it is coming from the base of the toilet ?

Today it was really bad after I thoroughly cleaned the black tank and added liquid deodorant chemical directly into the tank. The chemical smell became so bad that we had to open all the windows and doors. The smell never subsided all day? I decided to crawl up on the roof to see if I could verify the black tank gases were going up to the roof vent (directly above the back of the toilet). I thought for sure the smell would be strong at the roof stack vent, but to my surprise, it was very faint? I now highly suspect the vent stack pipe has an obstruction or was not plumbed properly? What do you recommend to verify the black tank vent stack is plumbed and / or is working properly? If it is not a vent stack problem, could it be the seal on the toilet base mounting flange causing the problem?

Dealer and I are both at a loss as to what to do next? Any suggestions would be appreciated.

G.S.

Admin Note: Moved from ATF to Plumbing forum for discussion among members. Issue has also been sent to the factory for input.

 

[Goldenwingers]

Does your toilet burp back when you flush it? Mine did when we first got it and I also had a strong odor in the trailer. I concluded my vent was stopped up and maybe I was just lucky but I filled the toilet all the way up to the rim and flushed it and and the pressure from the full bowl of water seemed to have cleared the vent and it has not burped back since nor have I had any odor since I did that. Not sure this will help but It couldn't hurt to try it.

Don

 

[Forrest Fetherolf]

fishn,

Are you connected to a sewer dump with the black tank valve open?
If so, do not leave the valve open as sewer gas can enter the tank.

Does the toilet flush ball valve hold water in the toilet bowl when closed?
If not, the flush ball valve is not sealing properly allowing sewer gas to enter the bathroom.

If none of the above, then I would suspect the holding tank is not sealed properly or vent stack is not connected properly to holding tank.

Forrest

 

[Jimmyt5]

This is a long shot, some thrones have a small overflow hole in the front under the lip. Some guys have said that they had problems with that letting gas back....

 

[Jburks]

We have a 2008 Sundance 2900MK and had a problem like this, we looked high and low trying to find the culprit, finally started looking at the valves and discovered the sewer valve label and the grey 2 label were reversed, I moved the labels and no more odor. This may or may not cure the problem but I would check. from front to back the labels on our 5er are sewer, grey 2 and grey 1. I hope this cures the oder for you.

 

[flyfishing48]

jburks
I am a little puzzled how switching the labels solved your problem..........unless you are keeping the gray 2 valve open, which in this case was the black???

 

[Oldlthrneck]

I think that was his point. The valves were mislabeled and they were keeping the wrong valve open.
Fred

 

[SmokeyBare]

But... if no valves are left open... and you allow the holding tanks to do their job (hold both black and gray drain water) ... the sewer gas that comes through the Campground's Sewer collection pipes can not rise through the vents of the RV.

I tend to allow the holding tanks to fill up... and then when they get close to full... I drain first the Black water tank... and once that is empty and sani-flushed... I then drain each gray water holding tank.

Works for me !

Marv

 

[Jburks]

By switching I was opening and closing the correct valve

 

[creeper]

I had the same problem with my Class A... I used a shark fin and Geo method and the problem went away.

 

[red4re]

I have a similar problem and I just posted it to Ask the Factory. My bad odor is coming through the AC vents in the trailer. When I dump the tank, it will run you out of the camper. Next time I dump, I will make sure the AC is off. Anyone else have this problem?

red

 

[fishn2dmax]

Red4re,

I haven't run my A/C to see if the black tank smell problem gets worse with A/C on? I believe we do have similar issues. After we dump the black tank after a trip, the smell will drive you out of the coach for hours. The smell is always worse if the coach is moved or while the black tank is being drained. We have ruled out the ball valve on the toliet since it holds water and seems to open and close very well.

In your case, the A/C should be recirculating the inside air, so it makes me wonder if it is really A/C related or if the A/C is just spreading the black tank ( venting problem) smell around the coach due the air recirculation inside the coach.

I highly suspect my trailer has a black tank venting problem. I'm thinking about putting a water hose down the black tank roof vent and then filling the vent pipe with water to see if it has an obstruction and / or is connected to the black tank properly. A vent pipe water leak should be very visible in the front storage area where the pipe turns to go down into the Black tank. I'm also planning to test the toliet flange / base seals by completely filling the black tank with water via the toliet and then all the way up to the bottom of the toliet ball valve. If a water leak is found using this method, it could expain the black tank smell in our coach's.

 

[fishn2dmax]

UPDATE:

After months of frustration trying to solve what was causing the black tank smell in the bathroom - The toliet didn't appear to be leaking and the bowl held water. I decided filled the black tank with water from the top of the Black tank roof vent. Right away I found a leak at the first elbow ( located in the front storage area) that turns down from the roof stack toward the black tank. After I pulled the joints (at the elbow) apart, I found NO glue was used on the joints? I again filled began filling the tank from the roof stack until the black tank was full and coming up into the toliet base. Once again more leaks found on the large ABS pipe to the toliet flange. A major leak was found at the toliet flange and the rubber base seal above the toliet flange. I now have my trailer at the dealer to fix the leak issues on the toliet ABS toliet flange and replacement of the base seal.

Someone at Heartland must have had a really bad day when putting the ABS fittings together - Most joints on the black vent stack looked to have little or no glue?

If you a experience persistant chemical or bad smell in the bathroom ( that is not due to you
You may want to have the toliet base seal hydrostatically ( water) tested and the ABS pipe joints checked.

 

[Sundance_kid]

Glad to hear you finally found the problem, so your thinking the trailer was made Monday or Friday, right!!!

 

[red4re]

I have a similar problem and I just posted it to Ask the Factory. My bad odor is coming through the AC vents in the trailer. When I dump the tank, it will run you out of the camper. Next time I dump, I will make sure the AC is off. Anyone else have this problem?

red

Update:

I bought a couple of those spinning vent covers to help out with the odor. It was my Galley grey tank that seemed to be causing all the stink. When I removed the factory vent covers on the roof, it appears that the factory vent covers were made for 1 1/2 inch vent pipe. The pipe used was smaller than that and left a gap all around the vent pipe leading back into the rv roof structure. I caulked that gap up and the odor problem seems to have stopped coming in the coach through the ac. The new spinning vent covers I bought are also for 1 1/2 inch vent pipe. So I go back to the RV store to see what else they have. All the vents and vent accessories are for 1 1/2 inch vent pipe. The instructions on one even said that if less than 1 1/2 inch pipe is used, make sure you caulk the gap so any odorous gases do not come back into the rv through the gap. The person helping said 1 1/2 inch is standard for venting in rv's and he was not aware of how I could adapt those spinning type covers onto the smaller diameter pipe I have.

Again - It's the Little Things.

By the way, I could feel cold air coming out of the gap before I caulked it when the ac was running. SO I am pretty sure this has fixed the smell, but I have only camped once since I fixed it. Going this weekend and will test again to make sure.

Either way, the improved spinning vent covers will not work because of the skinny pipe used.

Red

 

[SmokeyBare]

Red4Re,

Perhaps you could increase the small pipe size... Home Depot or Lowe's may have an increasing coupling... to bring it up to 1 1/2 inch size.

When you said you felt "COLD" air coming from the gap around the pipe before you used calking... It just could be that there are a few leaks in your A/C duct work.

First place I'd look would be at each end run of the duct work... by opening the ceiling vents at the far ends of the RV.... using a hand mirror and flashlight... look to see if there may be a opening directly into the Attic area of the RV.

IF So... It's not a real problem blocking the duct work...

Just my thoughts...

Marv

 

[red4re]

Red4Re,

Perhaps you could increase the small pipe size... Home Depot or Lowe's may have an increasing coupling... to bring it up to 1 1/2 inch size.

When you said you felt "COLD" air coming from the gap around the pipe before you used calking... It just could be that there are a few leaks in your A/C duct work.

First place I'd look would be at each end run of the duct work... by opening the ceiling vents at the far ends of the RV.... using a hand mirror and flashlight... look to see if there may be a opening directly into the Attic area of the RV.

IF So... It's not a real problem blocking the duct work...

Just my thoughts...

Marv

Thanks - I will look at it this weekend. I had the same thought. It can't be leaking too bad, as I have good airflow through all vents and it cools very well.

red