Grey Tank Odor

Update. Spoke to the service manager today. He got ahold of the factory and they think the problem may be in the vent line itself. Perhaps a poorly glued joint or perhaps it was missed. So the next step is to remove the shower, toilet and one of the cabinets. That way the vent line can be accessed. Both grey tanks are tied into one vent line. We will see what happens then.

bad99ram wrote:
I have a 2013 Jayco Premier 351MKTS. I am having a problem with a strong sewer gas type odor coming into the unit when I use the Bathroom fan or Fantastic fan. Both fans are set on exhaust. It is most noticeable under the Kitchen sink , but sometimes comes out from underneath the bathroom sink. Both air admittance valves under the sinks have been replaced and the vent thru the roof has been checked and is clear of obstructions. Does anyone have any ideas what else to check ? Its at the dealership now and the service manager has verified that there is a problem but thus far has not found a solution.

I have a similar problem, the issue is that the rv manufactuers have little idea how things work. What you have I belive from reading your post is valves ment to alow your tank to drain installed under your sinks. This is used in houses and even buildings sometimes and generaly are called studer vents. They are similar to a check valave and are designed to allow air to go into the pipe and check to prevent the tank from venting. This works fine on standard plumbing but when you have what we have and you fill a tank by draining a sink you are displacing the air with water and actually presurising the tank. These valaves are not made to hold back presure so when you drain your sink the tank burps air out of the valave and under your sink. Sadly the only thing you can do is either flush the tank well and often to keep odors out or vent the pipe to the outside. The valaves are not bad just miss applied.

I know sucks don't it. Seems like someone who builds rvs would have figured this out by now. I have one set up like this also. still thinking about the best way to permantly fix it.

We were having the same problem which we solved by cracking a window some when we ran the Fantastic fan. The fan has to get make up air for what it exhausts and I feel it was sucking the outside air down the grey water tank vent line and then past the water in the p- traps. I also started putting black tank chemical into the grey tank. Haven't had any more problems since we started doing the window and chemical.

We have two grey water tanks, one for the bathroom and one for the kitchen sink. Only the bathroom one vents through the roof. The kitchen one vents through the side wall behind he sink area. This was the main culprit I believe.

I was having the very same problem. I checked everything and couldn't find the problem. I bought a flush king and started back flushing my grey tanks and the problem is gone. No odors for the past 3 years. Hope this helps.

RT

Check your vent pipe. Sometimes it comes loose inside the wall from improperly joining the pipes or it could be cracked. Seen both.

Two possibilities:

Is it possible the traps under the sink are at an angle that prevents a water barrier from completely forming in the trap(s). The fans suck the gases pass the poorly formed water barrier in the trap(s).

Or

I would suspect a crack or improperly sealed joint in the plumbing or top of the tank. The fans are sucking the smell into the RV probably from around the gaps in the floor and cabinets where the sewer pipes enter. You should be able to test this by placing a wet rag to block any gaps or openings around the sewer pipes if the smell stops you'll know its coming from below the floor.

If all else fails we use the toilet deoderizing chemical in our kitchen sink grey tank whenever it begins to smell from food debris buildup. The smell goes away quickly.