Quick Help! Black Tank Vent Issue

["EZ"]

Help! OMG!!! All of a sudden the black tank vent is leaking fumes inside our RV. We thought it was coming up from the toilet when we would flush. But I've tracked the smell to the hallway closet next to the bathroom where the washer/dryer would be if we had one. We're using the closet for storage of towels etc. The black tank vent pipe is a black PVC pipe that goes up the wall of the closet to the roof. It has a "T" that send pipe into the bathroom side. I can't see exactly where it goes but I assume the toilet.

I climbed up to the roof to take a peek. There is a small wasp nest inside the pipe of the vent. It was blocking 3/4 of the pipe. Would that be enough to cause the fumes to back up inside the coach? I'm thinking of putting a water hose into the pipe and turning it on to see if the pipe is blocked. Is this OK? I don't want water to come pouring out inside the RV!! I'm assuming the water would go down the pipe and into the black tank, right?

Let me know what you think before I do something stupid.

 

[Neal]

Doesn't sound "EZ"! Obviously making sure your vent is working properly but do you have a black tank rinse system? In my coach the black tank rinse actually comes up under the half bath sink and goes through a check valve type system then goes back down into the black tank. Mine had a cheap plastic crap setup I changed with a brass setup. If you have such a thing, it could be a cause.

 

["EZ"]

Doesn't sound "EZ"! Obviously making sure your vent is working properly but do you have a black tank rinse system? In my coach the black tank rinse actually comes up under the half bath sink and goes through a check valve type system then goes back down into the black tank. Mine had a cheap plastic crap setup I changed with a brass setup. If you have such a thing, it could be a cause.

Lets hope that's not it. I think the wasp nest had the tank vent blocked enough that it may have sucked the P-trap dry in the washing machine closet. We don't have a washing machine so the drain is open and 90% of the smell was coming out of that closet. I assumed it was the toilet at first but it got worse and worse even after me draining both the black and grey tanks and rinsing the black tank about 6 times. I also went to Wal-Mart and grabbed some TST Tank stuff to pour in the black tank to kill the smell. I think it really helped as the smell is almost gone now. I'm still thinking of using a hose and water to clear the tank vent. I knocked the wasps nest down the vent from the roof so now it's down inside the pipe somewhere. I'm hoping the water will push it to the tank below. What do you think?

 

[bpaikman]

Lets hope that's not it. I think the wasp nest had the tank vent blocked enough that it may have sucked the P-trap dry in the washing machine closet. We don't have a washing machine so the drain is open and 90% of the smell was coming out of that closet. I assumed it was the toilet at first but it got worse and worse even after me draining both the black and grey tanks and rinsing the black tank about 6 times. I also went to Wal-Mart and grabbed some TST Tank stuff to pour in the black tank to kill the smell. I think it really helped as the smell is almost gone now. I'm still thinking of using a hose and water to clear the tank vent. I knocked the wasps nest down the vent from the roof so now it's down inside the pipe somewhere. I'm hoping the water will push it to the tank below. What do you think?

(chiming in, finding this a VERY interesting issue) I’ve a oouple of questions : 1. Is a vent line such as you’re describing waterproof? It’s designed to transport gases, not liqiids, so I’m wondering if it’s sealed at every joint? Is that why you’re concerned?
2. Once when we had our RV in for repairs, they installed screen caps over the … heater vents I think…. to keep wasps out. I wonder if that could be done to all ventts? And why isn’t that routinely done…$$ I guess.
(I’m currently taking that RV owners course -homestudy version first, planning to take the live class in Athens Tx later in the year when it’s cooler. The wastewater section is later, and I’ll pay special attention to that issue when Ii get to it! ?

 

["EZ"]

(chiming in, finding this a VERY interesting issue) I’ve a oouple of questions : 1. Is a vent line such as you’re describing waterproof? It’s designed to transport gases, not liqiids, so I’m wondering if it’s sealed at every joint? Is that why you’re concerned?
2. Once when we had our RV in for repairs, they installed screen caps over the … heater vents I think…. to keep wasps out. I wonder if that could be done to all ventts? And why isn’t that routinely done…$$ I guess.
(I’m currently taking that RV owners course -homestudy version first, planning to take the live class in Athens Tx later in the year when it’s cooler. The wastewater section is later, and I’ll pay special attention to that issue when Ii get to it! ?

The vent is a PVC pipe that comes up through the wall from the black and grey tanks with stops along the way to the washer drain and the toilet then on up to the roof where is comes out. Mine has no screen over it but it has a cap on it that would keep a bird out. I'm assuming it's pretty well sealed up from bottom to top.

I finally solved my stinky issue with adding a cup of water to the P-trap in the washer drain pipe. Just poured the water down the pipe. (We have no washer just the hook ups for one) Problem solved. No more stink. Someone told me that when I drain the grey tank that if I hear a big WHOOSH!! at the end, that it could pull enough vacuum to empty the P-traps so I needed to pour water down the washer drain and run a little water in the sinks to re-fill the P-traps again. It worked!! ?

 

[MapNerd]

Glad you figured it out EZ. I had a similar problem a few days ago. Couldn’t figure out where the sewer smell was coming from, but then I remembered I had brussel sprouts the night before. I was just walking around farting.

 

[John&Andrea]

I’m glad is was an easy fix for you. I know it was a pain tracking it down.

 

[Gronk]

If you don't use the drain you can either put a 1/4 cup of cooking oil in it to stop evaporation, or get a test plug like this:

 

["EZ"]

If you don't use the drain you can either put a 1/4 cup of cooking oil in it to stop evaporation, or get a test plug like this: View attachment 7696

Great idea! I actually found a plastic cap in the bottom of the washer/dryer cabinet. I didn't know what it was for. I'm surprised I didn't throw it away. LOL. I put it into the drain pipe and it fit very snuggly. Guess that's what it was for! ?

 

[JRS]

Glad it was a dry P-trap. May want to spray to kill the wasps? Don't want them to re-establish another nest. Maybe use a shop vac to get the old nest out?

 

[AbdRahim]

screen caps over the … heater vents I think…. to keep wasps out.

I did this on my first trailer. I have been meaning to do iton the MH and haven’t gotten to it. I put them on the A/C units, the front engine grill and air intakes. Critters of many sorts can create problems.

 

["EZ"]

screen caps over the … heater vents I think…. to keep wasps out.

I did this on my first trailer. I have been meaning to do iton the MH and haven’t gotten to it. I put them on the A/C units, the front engine grill and air intakes. Critters of many sorts can create problems.

I thought about putting screen covers on the vents up on the roof. Probably a good idea.

 

[Suncruiser owner]

Help! OMG!!! All of a sudden the black tank vent is leaking fumes inside our RV. We thought it was coming up from the toilet when we would flush. But I've tracked the smell to the hallway closet next to the bathroom where the washer/dryer would be if we had one. We're using the closet for storage of towels etc. The black tank vent pipe is a black PVC pipe that goes up the wall of the closet to the roof. It has a "T" that send pipe into the bathroom side. I can't see exactly where it goes but I assume the toilet.

I climbed up to the roof to take a peek. There is a small wasp nest inside the pipe of the vent. It was blocking 3/4 of the pipe. Would that be enough to cause the fumes to back up inside the coach? I'm thinking of putting a water hose into the pipe and turning it on to see if the pipe is blocked. Is this OK? I don't want water to come pouring out inside the RV!! I'm assuming the water would go down the pipe and into the black tank, right?

Let me know what you think before I do something stupid.

No water should go anywhere except into the tank. If it comes out somewhere else, you may have a break in the pipe. I would definitely get rid of the wasp nest.