We are having a problem with sewer odor from the bathroom area that occurs only when we are traveling. I have searched but found no definite help.
Anyone have any ideas about the cause of this?
Vent needs replaced, under sink, available at Home Depot. Search vent odor on Forum
Vacuum (lower air pressure) in the bathroom than in the gray and/or black tank.
One of these (or similar) on the roof tank vent will lower air pressure in the tank:
Rotating Plumbing Vent Cap - Cyclone by Camco - PPL Motor Homes (http://www.pplmotorhomes.com/parts/rv-vents/rv360-vent-cap.htm)
Sure, there could be other, more involved issues-- could be a mud dubber next blocking the roof vent, could be that the PVC pipe to the roof vent has fallen into the tank, failure of an air inlet check valve Shop Keeney Mfg. Co. Plastic Mechanical Plumbing Air Admittance Vent at (http://www.lowes.com/pd_24372-143-85539K_0__?productId=1069119&Ntt=pvc+air+admittance+valve&pl=1¤tURL=%3FNtt%3Dpvc%2Bair%2Badmittance%2Bvalve&facetInfo=), etc.
BTW, allowing outside air through the dash HVAC raises air pressure in the coach and will help minimize odor.
As always Brett is the definitive source of information but I would start with the air admittance vent
Tim-- you are correct.
Very easy to do the "sniff test". If odor is worse in the cabinet, sure enough, that is your source.
There may be a second vent behind the toilet bowl in the cabinet. Mine has one.
I can find no vent in any of the places suggested, so I guess I need the more expensive solution that Brett suggested. Thanks.
Could also be behind the washer if you have one. Both our shower one and our washing machine one are there.
Royce,
Can you locate the SOURCE of the smell-- where is it strongest?
These vents don't look like vents. They are like a black plastic canister atop some black PVC type pipes that are vertically mounted. It doesn't look like it but they are threaded and just screw on the top of the pipe. Inside is a one way flapper valve which allows air into the tanks. Once the flapper ages and becomes stiff and deformed it can also allow sewer gas to get up into the cabinets and eventually the living area.
These valves can be located in the cabinets behind the toilet, under the bathroom sink, in the closet designed for the washer/dryer and under the kitchen sink. It all depends on where the tanks are located. I guess they could be anywhere they can be concealed. They are usually under $10 so once you take one off just replace it with a new one. They are not worth trying to fix.
Makes a difference if rear windows are open or closed, as well as the fantastic fan vent. The wrong combo will suck sewer fumes, far be it from me to explain why.
ABS, actually. If you search the forum for "air admittance valve" you'll find pictures.
Air Admittance Valves, aka "Stinky Coach Syndrome" (http://www.foreforums.com/index.php?topic=12120.msg62530#msg62530)
The coach is parked at home and there is no sewer odor. It occurs only when we are traveling. No smell at all now.
That's because it's a dynamic air pressure issue. I suspect lower air pressure in the aft part of the coach is allowing noxious fumes to flow from a higher pressure (the grey/black tank) to a lower pressure area (the back half of the coach while you're going down the road.) Try adjusting venting, it's the only thing I've found to work.
Yes, picture is the second link in my first post. Under $6 at the box stores. And the rubber gaskets DO get stiff and fail. Easy to unscrew and replace. But, it the odor is not stronger under the cabinet, unlikely that is the source of the odor.
There will be a vent - all sinks have a vent - all the FT's I have owned have a vent (admittance vale at the top of a large diameter PVC. It will be in the rear, maybe corner of the cabinet the sink is mounted in. The air admittance valve will screw into the top. They are intended to be one way, but when they fan the odors can come back into the coach. When you drive down the highway, a small vacuum differential is created inside your coach vs. outside air pressure. If you valve fails, this differential caused the air in the tanks to flow back into the coach, with the resulting odor.
We all seem to have different experiences with the stink factor, when I first noticed the issue, thought sure it was from the black tank, WRONG, was from the grey tank with old soay water, I found it by dumping a bottle of KenKleen or something like that down sink & shower, BINGO bas order went away. No more problems, before I store coach, I treat each empty tank and never any stink, I du use a little water making coffee & clean up, but never use the toilet until am on the road. ;D
Everyone may experience this sooner or later. Had this same problem. Replaced both vents under sinks//they are cheap. Santitized both tanks/put in Dawn into holding tank. add Ice and drive for 5 to 10 miles start and stopping best. If still there add country time lemonade powder to holding tank. You should have no issues after that.