New Trailer and sewer odors

[Rick A]

We had our new 2006 Wildcat 31QBH out for the first time with full hookup. We were getting sewage odor from under the kitchen cabinets. The valve for the galley and bathroom grey tanks were open, and the black tank valve closed. I checked all the fittings for the traps under the sink and they are tight. When I checked the pipes, there are the two traps for the double sink, they connect to a single pipe that runs to the holding tank. That pipe is connected to a T. From that T, a pipe continues to the tank, and there is another pipe about 3" long that goes straight up and terminates at a funny looking cap. All I can see is the cap has open slots on either side of it, and you can see a spring inside it. The pipe that runs to the tank then has another T where it goes down to the tank and the vent runs up alongside the fridge through the roof. At times the odor would get very strong. I double checked all the sewer connections, and everything was tight, and no odor could be smelt at the connections, it was only under the kitchen cabinet. Any ideas what this funny looking cap could be? I suspect this is the culprit.

[Rick A]

We had our new 2006 Wildcat 31QBH out for the first time with full hookup. We were getting sewage odor from under the kitchen cabinets. The valve for the galley and bathroom grey tanks were open, and the black tank valve closed. I checked all the fittings for the traps under the sink and they are tight. When I checked the pipes, there are the two traps for the double sink, they connect to a single pipe that runs to the holding tank. That pipe is connected to a T. From that T, a pipe continues to the tank, and there is another pipe about 3" long that goes straight up and terminates at a funny looking cap. All I can see is the cap has open slots on either side of it, and you can see a spring inside it. The pipe that runs to the tank then has another T where it goes down to the tank and the vent runs up alongside the fridge through the roof. At times the odor would get very strong. I double checked all the sewer connections, and everything was tight, and no odor could be smelt at the connections, it was only under the kitchen cabinet. Any ideas what this funny looking cap could be? I suspect this is the culprit.

[charliez]

That is a vent for the sink drain. It's there to allow air to enter the system wehn water flows down it, but stop air and gasses from coming out. It may be faulty.

[Rick A]

Thanks for the info charliez! Is there any way to test it, or should Ijust replace it? Where would I find a new one?

[CD]

Rick A
Other than the obvious (a RV parts store) someplace like Home Depot would have it and probably for less money.

[TTT1953]

Rick, Before replacing the spring loaded vent valve, you might check the roof vent to make sure it isn't plugged. I tie a 2oz. fishing sinker onto line and drop it into the tank from the roof. If the vent is plugged in hot weather, gasses can build up forcing the spring loaded relief to do exactly what it is designed to do, vent pressure. You might also keep the gray water valves shut except when you need to dump them. They provide a path for sewer gases to back up into your tanks and ultimatly into your rig.

[Ray,IN]

Yep! There is no water barrier on the CG septic hookup. Leaving your tank valves open may be allowing odors to backflow into your tanks. Then your only protection from these odors are the drain traps under the sinks and other drains. This is an unusual condition though, most always I leave the grey valve open and don't have odors. Does this happen at different CG's or just one?

[Rick A]

Since this is a new trialer, and it was our first trip with sewer connection, I donlt know if it is an isolated case or not. I did check the vent under the sink, and it was not even hand tight. The valve it self looks to be fine. I tighened up the valve and hopefuly that will solve the problem.

......I don' t leave the discharge hose in the sewer system with a donut.....when I was in Fla. this winter there was a low pressure sewer gas/air coming out of the sewer hook up and it could backup into the trailer....when I dumped I hooked up and then replaced the sewer cap when finished.....I wasn't going to take any chances with sewer gas backing into the trailer......bad smells I can deal with methane I won't......BOOM!......geofkaye

[skipper]

Glad you found out the cause ,for those that think there is no trap in the system ,look at the end of most flex hose to the fitting ,donut ,or other fitting the hose must go up to empty water and waste fall down and exit the trailer higher than the hight of the donut connection ,and we know that water seeks its own level ,water will only exit the hose when there is water pushing it up and over the hump and as soon as the weight of the water is gone and water falls to exit the hose some will flow back in the hose and collect making a seal in most cases. A dip in the flex hose can be made by placing a object that the water must get over like a six inch stone,Log , boars,etc. that would make a dame to stop the gas. Taking the hose loose is a PITA and stinks too .Skipper entry level over fifty years