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View Full Version : Weird issue with new 2nd ac unit (smell)


davidcyndi
04-15-2013, 06:25 AM
Went camping for the first time since having our 2nd ac unit installed. The unit is in the rear of the rv. Its not ducted it just blows from the unit. I had both units on and had to empty the grey and black tanks. The rear unit started blowing foul air into the trailer when I did this. I mean the bog of eternal stench kind of foul smell. woooaaaaahhhh it was bad. The smell continued to blow out until I removed the poop tube from the trailer. Now while the poop tube was connected I had all the valves closed (grey1,2, and black) but it seems like it was pulling the gas from the sewer into the trailer via the poop tube and out the ac. Like I said once I removed the poop tube from trailer it stopped. And it only blew out the rear new ac unit. Any ideas why this happened? or what happened?

JRTJH
04-15-2013, 06:51 AM
When the hose was connected to the black tank and the valve was open, you probably were pulling sewer gas up the vent stack and into the fresh air mixer port on the AC. When you closed the valves, it continued to pull the stench until pressures normalized. Next time you dump, if it happens again, then do a "controlled study" and put a plastic bag over the vent stack on the roof. See if the stench goes away with that effort. I'd bet your AC is pulling in sewer gasses from the roof vent.

It is also possible that the hot air from the AC condensor was blowing toward the bathroom roof vent which was open, forcing the black tank roof stack gasses into the RV through the open ceiling vent. Either way, the only common link is the sewer gasses coming up the black tank roof vent which is located near your AC.

We had a reversible FanTastic roof vent fan on our HR bathroom vent. The black tank vent stack was about 1 foot from the bathroom ceiling vent and we could never use that fan to pull air into the bathroom without getting the black tank smell because of the location of that vent stack.

davidcyndi
04-15-2013, 07:16 AM
When the hose was connected to the black tank and the valve was open, you probably were pulling sewer gas up the vent stack and into the fresh air mixer port on the AC. When you closed the valves, it continued to pull the stench until pressures normalized. Next time you dump, if it happens again, then do a "controlled study" and put a plastic bag over the vent stack on the roof. See if the stench goes away with that effort. I'd bet your AC is pulling in sewer gasses from the roof vent.


Sorry didn't even think about that. We are new at this and this was only our 2nd trip. I think next time If we have to dump while we are still using the trailer I will just turn off the 2nd ac until I am done dumping the doo. Thanks so much for answering my question.(tx)