Went on maiden trip with our new KZ Spree 329 IK. We were in full hook up site. On departure our black tank was 3/4 and grey tanks 3/4 full. I've RVed for a number of years (being our 3rd RV) and think I know how to properly dump. Opened black tank valve dumped great, then closed valve when empty, opened grey dumped fine and closed valve. Proceeded to hook up factory installed black tank flush system. Opened black tank valve and turned on water hose to flush line.Wife immediately yelled there in bad sewer odor in our travel trailer. I tunrned off water to black tank flush and went inside and boy it was a horrible smell. Confirmed on panel all tanks read empty too. No leaks anywhere, no evidence of any problems, but highly unsusual for the smell to be so pronounced when using the factory installed flush.Any advice out there on why this happened?

Overhead vents open will draft stink from sewer into/through camper.Really pronounced if an exhaust vent fan is blowing.Good Luck, Mike

Maybe your backflow preventer blew off the line. Mine was not installed properly from the factory but didn't notice until there was water pouring out of the underbelly.

HappyKayakers wrote:Maybe your backflow preventer blew off the line. Mine was not installed properly from the factory but didn't notice until there was water pouring out of the underbelly.Checked the backflow preventer also as it is on a closet and very accessable. No leaks there. There is only the odor issue.

I think it's normal. After 12 years of this, I find it's hard to escape odor.

Did you have any fantastic or ceiling fans running with no windows open.That's what happened to us a few days ago.While the dump vlave was open for a few minutes, the fan sucked the smell up through the sinks.

Black tank odor in RV when dumping | Good Sam Community

popeyemth
Explorer
Aug 20, 2014
Overhead vents open will draft stink from sewer into/through camper.
Really pronounced if an exhaust vent fan is blowing.
Good Luck, Mike
HappyKayakers
Explorer
Aug 20, 2014
Maybe your backflow preventer blew off the line. Mine was not installed properly from the factory but didn't notice until there was water pouring out of the underbelly.
NCKZ_Camper
Explorer
Aug 20, 2014
HappyKayakers wrote:
Maybe your backflow preventer blew off the line. Mine was not installed properly from the factory but didn't notice until there was water pouring out of the underbelly.

Checked the backflow preventer also as it is on a closet and very accessable. No leaks there. There is only the odor issue.
2oldman
Explorer II
Aug 20, 2014
I think it's normal. After 12 years of this, I find it's hard to escape odor.
dan-nickie
Explorer
Aug 20, 2014
Did you have any fantastic or ceiling fans running with no windows open.
That's what happened to us a few days ago.

While the dump vlave was open for a few minutes, the fan sucked the smell up through the sinks.
hawkeye-08
Explorer III
Aug 20, 2014
dan-nickie wrote:
Did you have any fantastic or ceiling fans running with no windows open.
That's what happened to us a few days ago.

While the dump vlave was open for a few minutes, the fan sucked the smell up through the sinks.

Curious how you could get smell through sinks.. unless your traps are dry..
dougrainer
Nomad
Aug 20, 2014
1. When flushing with a Black tank Flush, you WILL get any tank odor out the top roof sewer vent. The top vent cap may be on too tight and not allowing the tank to vent properly or the abs up pipe is not sealed where it goes thru the roof cavity.
2. It is possible that the back flush check valve does NOT leak water but may leak gas, but I doubt it as there is water constantly going thru it, so no gas can come back up.
3. Black tank odor is RARE IF you use chemical. Using chemical not only breaks down the solids but makes the tank smell much nicer and should not have that outhouse smell.
4. Dump your tanks and flush. put a qt of pine sol in the black tank. Flush your black tank with the flush system. See if you get the pine sol smell in the RV. If NOT, then your odor is from the gray tank. Doug
popeyemth
Explorer
Aug 20, 2014
hawkeye-08 wrote:
dan-nickie wrote:
Did you have any fantastic or ceiling fans running with no windows open.
That's what happened to us a few days ago.

While the dump vlave was open for a few minutes, the fan sucked the smell up through the sinks.

Curious how you could get smell through sinks.. unless your traps are dry..

Sometimes the vacuum breaker sticks and the outrush of grey water will suck (via the vacuum created ) the traps dry.
Air has to replace the gray water and if things don't work right that air will come from the sink or shower trap.
NCKZ_Camper
Explorer
Aug 20, 2014
I do think the roof vent in the bath was open, but not sure if fan was running. I did notice this morn when I checked that both my kitchen sink and bath sink have venting under the sinks and not through the roof! Maybe the pressure forced some gas from under the sink vents?!?
popeyemth
Explorer
Aug 20, 2014
We get odors if the bath vent is open.