Air Conditioner Odor

[stevebotts]

When using our second AC in the bedroom, we have noticed an odor, sort of like sewage. This does not happen all the time but sometimes is so bad we have to turn the unit off. We do not have a washer/dryer installed in the closet. I do not notice any odor coming from the toilet or sink, just from the AC. Does anyone have this problem and/or if you did, what was the solution.

 

[TXBobcat]

We have a similar problem. I did find one thing that might contribute to it but not sure it is the problem.

See this thread about the ball in the toilet.
//heartlandowners.org/showthread.php?p=38901#post38901

If there is no water in the bowl or the ball is slightly open it can draw odor from the toilet. But I still have a slight smell when I run the front AC.

 

[sealman]

If you are connected to the sewer and have the grey water valves open, it is a diect vent to the sewer via every drain in the 5'er.
John

 

[linuxkidd]

sealman: you are correct, except that every drain that leads into the grey tank passes through a trap. If you've run water into the drains in the last 2 weeks, I'd imagine that there would be enough water in those traps to prevent tank odors from entering the coach.

We too however have experienced black tank odors from the ball valve not being closed all the way... We have now developed a habbit of lifting the foot valve completely after each flush. This has solved our problem. I believe there is a post someplace that says dometic has a new valve assembly of some sort and will send replacement parts free of charge built to the new requirements.

Hope this helps...
LK

 

[Oldlthrneck]

If you have a washer prep in the closet with no washer hooked up, put a little water down the washer drain. That trap is dry and will allow fumes to come up through the sewer hose. Every time we start smelling sewer smell it comes from the front closet. You have to replenish it now and then as it will splash out when you travel.
Fred

 

[stevebotts]

Thanks for the suggestions. We have checked the toilet and that does not seem to be the problem. Also, our washer drain is capped off and appears to be very tight. Any other suggestions? Last night the odor was really bad but after about 5 minutes abated. Of course the damage was done and all the windows had to be opened to get rid of the smell. Seems to be an off and on thing.

 

[htneighbors]

Is it possible for rooftop sewer vent smell to enter via an AC unit? Just wondering.

 

[nscaler2]

Is it possible for rooftop sewer vent smell to enter via an AC unit? Just wondering.

Good guess H.T. That's what I figured is happening. Depending on what direction the breeze is blowing from, grasses from the toilet vent may be being sucked back into the unit from the air conditioner. That would explain why it is so intermittent. Good guess!!

 

[Shadowchek]

Also during the winter when cookin or just breathing for that matter moisture builds up in the air and as the warm moisture laden air rises the highest point is the bedroom A/C . Over a period of time mold can form on the evaporater coil inside the unit. I know there is some kind of spray for this I believe you can get it at an auto parts store or a place that works on automotive air systems. If this is the problem it will greatly reduce the smell. Once that smell gets into the Aluminum of the evap coil you can't always completely get rid of it. If this seems to be the problem talk to an automotive A/C guy. With the bedroom A/C I believe it doesn't have any ductwork so it has the same amount air entering and exiting the unit which should not cause a pressure differnce in the bedroom. If there isn't a pressure difference it shouldn't be pulling air from the outside or the drains especially past the traps if they are full. It would just recirculate the air that is already there. Not that everything always works exactly like it is supposed to. Just some thoughts and possibilities not trying to confuse anyone.

 

[Rickhansen]

P-traps will stay "wet" when used frequently. For long-term storage (not in freezing conditions) or like the trap for the washer prep without a washer installed, fill the trap with water then pour in about 1/4 cup of vegetable oil. The oil keeps the water from evaporating out of the trap. When you eventually use the drain, the water will pour through or displace the oil and the trap will still function.

 

[rcobb]

We had this happen also.. I believe it is coming from the roof top sewer vent. I installed these on all of my roof vents a couple of weeks ago and have not had any more problems.

http://www.coilnwrap.com/more/Xtreme-Vents.htm

 

[mntnlife]

Have a ’08 BC 3500RL, I am getting a black water smell coming from the a/c vents when I run the kitchen water faucet. I climbed up and checked the roof vent while running the facet and noticed not much smell coming from the vent. I don’t believe that the a/c pulls in outside air so any odor coming from the vents would not circulate into the unit. All other facets, shower, and toilet have no effect on the smell, just the kitchen faucet. I have also replaced the one-way vent valve under the kitchen cabinet.

 

[Crista]

We also have the same problem. We have a 2010 Cedar Ridge and when I turn on the AC and go out of the trailer and come back in, the smell is horriable! I then have to turn it off because it smells like rotten eggs or a sewer smell. I have no idea how to fix it.

When using our second AC in the bedroom, we have noticed an odor, sort of like sewage. This does not happen all the time but sometimes is so bad we have to turn the unit off. We do not have a washer/dryer installed in the closet. I do not notice any odor coming from the toilet or sink, just from the AC. Does anyone have this problem and/or if you did, what was the solution.

 

[DavenKendra]

We have had the same problem when the black water tank is close to full. The black tank vent is located near the AC on the roof. For some reason fresh air is drawn in by the AC unit creating a positive pressure in the RV and when you flush the toilet it increases the output of the vent and completes cycle through the AC. Remedies: clear black water tank, don't flush when second AC is running.

 

[hoefler]

Remove the grill inside to your A/C. If the return air side is not sealed off completely from the attic, it can draw air from the attic. The sewer vents are not sealed from the attic. The vent pipes are stuck through a hole in the roof and a vent cap installed on top. The pipe is not sealed to the roof and the vent is placed over the pipe and also not sealed to the pipe. If the vent is in close proximity to the A/C, it will be more likely to draw air from the sewer vent. When second A/C's are installed, the installer needs to install block outs to the attic. I can't speak for the new Heartland models, but after removing the roof vent, I have never seen the attic blocked off when installing the second A/C.

 

[Brandon.Prewitt]

Ours does the same thing. Since my black water tank gauge is not accurate, the odor reminds me when to dump.

 

[zurn]

i had a smell problem with a mobil home i rented out. after looking for a long time, the problem was the sewer vent line was not connected to the roof vent allowing the sewer gas to exhaust into the attic. the fix was to glue a extension (pvc) through the roof.

 

[gratton]

I had the same problem with odors being pulled in the A/C unit from the black tank vent depending on which way the wind was blowing. Installed a Cyclone vent cover and problem solved.