Sewer gas issue

Executive wrote:

1. Ensure your P traps are functioning and full, including the washer one.

Our washer drains into the gray tank (not the black like the OP), and even though we use it all the time sometimes the p-trap on it dries out and it smells terrible.

To fill the p-trap,, you can't just add water to the unit--you also have to tell it to drain that water.

Sewer problems are usually caused by several factors. Start with the easy and proceed to the more difficult.
1. Ensure your P traps are functioning and full, including the washer one.
2. Ensure your roof vent is functioning properly. Did the tech drop his screwdriver or other object down the tube accidently? Perhaps lost a bit of plastic that's now wedged in the pipe? I'd remove the cyclone and run a good bit of water down that pipe to make sure it's not plugged in some way. May be a birds nest, hornets nest etc.
3. Clean your black tank well.
4. Don't poop in the rv. Well that one most likely won't work. :)...Dennis

fourmat wrote:
Return your roof vent pipe to the way it was before and I bet your odor problem goes away

Why do you think the cycolone may have caused the problem?

Return your roof vent pipe to the way it was before and I bet your odor problem goes away

I went to storage today and took it for a short drive. It appears the smell is coming from the wet bay and getting into the bedroom above. Many openings for a smell as they are there to supply heat. I am going to remove all hoses even though they are sealed. then scrub it well. Then see what happens. Running the ac with outside air and not the recirculate made a huge difference. A lot of great info to use for eliminating one thing at a time. One suggestion was to replace the vents under the sink. Could they go bad in a little over a year? At least i now know to be careful on the ac air part. We use all the drains including washing machine frequently. When the smell came i refilled all in case water had splashed out. Roads in WI are terrible. They have really gone to hell in past half dozen years. Thanks again for everything.

Replace your air admittance valves under your sinks. They do get brittle and stop working correctly which allows sewer smell to back up into the rig. Been there and done that a few times now.

hostage wrote:

rgatijnet1 wrote:
For whatever reason the vent on your roof is capturing the outside air and forcing it down the pipe in to your RV. If you have anything on top of the PVC pipe, try taking it off and see if that fixes the problem. If it does, just get a standard vent cap.

how could that be? the black tank only has one vent and thats the roof out to atmosphere; the only other is the toilet and the seal would have be shot(wont hold water) and surely a owner would know this
and the seal would have to be incredible worn for it to actually escape enough through this seal to cause a problem from driving down the road

He did say his washing machine dumps to the black tank, if the roof vent is catching wind and forcing gas out of the washer pipe he could smell it for sure.

hostage wrote:

rgatijnet1 wrote:
For whatever reason the vent on your roof is capturing the outside air and forcing it down the pipe in to your RV. If you have anything on top of the PVC pipe, try taking it off and see if that fixes the problem. If it does, just get a standard vent cap.

how could that be? the black tank only has one vent and thats the roof out to atmosphere; the only other is the toilet and the seal would have be shot(wont hold water) and surely a owner would know this
and the seal would have to be incredible worn for it to actually escape enough through this seal to cause a problem from driving down the road

There's a very simple reason how it could be. If you have a window open in the RV while driving, say the drivers window, the slipstream causes suction, which causes negative pressure inside the RV. That can cause holding tank fumes, grey or black, to be sucked inside the RV. Grey tank smells can be as bad as black tank smells.

Reasons are numerous but can include a dry P trap on the washer drain, a dry P trap on an unused sink, a weak seal in the toilet, etc..

Those old style dome vent covers on the roof use to be famous for allowing smells inside with the drivers window open. There are commercial devices for that, but I just put a bathroom sized PVC 'T' on the roof in place of those dome vents and the wind from driving, caused slight suction in the tanks which allowed opening the drivers window with no smells.

hostage wrote:

rgatijnet1 wrote:
For whatever reason the vent on your roof is capturing the outside air and forcing it down the pipe in to your RV. If you have anything on top of the PVC pipe, try taking it off and see if that fixes the problem. If it does, just get a standard vent cap.

how could that be? the black tank only has one vent and thats the roof out to atmosphere; the only other is the toilet and the seal would have be shot(wont hold water) and surely a owner would know this
and the seal would have to be incredible worn for it to actually escape enough through this seal to cause a problem from driving down the road

He did say that he had a "fan like thing" installed on the roof vent and then the problem started. I said to remove the fan like thing and see if that corrects the problem. Sort of sounds like a common sense thing to do to fix the problem. If something is catching the wind while driving down the highway, it can cause a lot of positive pressure inside the black tank and could easily escape past a seal.

rgatijnet1 wrote:
For whatever reason the vent on your roof is capturing the outside air and forcing it down the pipe in to your RV. If you have anything on top of the PVC pipe, try taking it off and see if that fixes the problem. If it does, just get a standard vent cap.

how could that be? the black tank only has one vent and thats the roof out to atmosphere; the only other is the toilet and the seal would have be shot(wont hold water) and surely a owner would know this
and the seal would have to be incredible worn for it to actually escape enough through this seal to cause a problem from driving down the road