Vent fan and odor from commode

[Zigpep]

Hello, we have a new to us 2005 31.5 Nuwa discovery America. We are fulltiming in it and are in the process of selling our 27 foot motor home and have been living in the fifth wheel for about 6 weeks. We really love the Nuwa and believe we have a quality fifth wheel however we are having a problem.
The shower is separate from the commode and The vent over the shower does not have a fan. The commode is across from the shower in a small separate room, the commode room has a vent with a fan and we are not having problems with odors in the commode room BUT When I open the vent over the shower to let moist air out of the shower area there is frequently a horrid odor that is obviously septic that comes in thru the open shower vent. I am guessing this is coming from the vent stack pipe that runs from black water tank to roof, it is in the commode area ( again no problem there). The shower vent is probably close to the stack.
I have 2 questions, first is it normal for there to be an odor from the black water vent stack/ pipe, I'm guessing that's a yes since it's purpose is to vent gases from the black water tank.
Second, will putting a fan on the vent in the shower solve this problem? And if so how hard is it to put a fan on the vent. There is no power running to this vent that we can see, no way to power it. We will have to add electrical wiring to it or has anyone heard of a battery powered fan?
Thanks zigpep

[12th_Man_Fan]

Are you sure it is not the vent under the bathroom sink. If the vent is bad or weak when you open the roof vent sometime that is enough pull to bring in smells through the sink vent.

[BB_TX]

coolmom42 wrote:

BB_TX wrote:
If the wind is blowing in the direction from the black tank vent toward the shower vent, then yes the odor will be there. Nothing to be done about that except keep the shower vent closed.

Adding a vent fan for the shower should eliminate, or at least minimize, the odor problem. Running power thru the ceiling would be difficult. A fan large enough to move much air would probably go thru batteries fairly quickly.

This last statement is not correct. Fantastic Fans use very little power.

I think the OP is talking about a regular battery powered fan, not one running from the coach battery 12 volt system. How long do you think a Fantastic Fan would run on a couple of D cell batteries? A few hours maybe? Or if it was a 12v fan, it would take 8 D cells, a pretty good size battery pack.

[rekoj71]

I was able to run wires through my ceiling but it wasn't easy, and it may depend on where your closest power is. A lot of RV roofs are trusses with styrofoam in between them. If you can obtain power from a source that is between the same trusses as the fan you are looking to power you might be able to poke a hole through the styrofoam to get to it.

If you take down the vent housing you might even find the vent pre-wired and the wires hidden behind the housing. If they aren't there you will still see the foam blocking around the vent opening. I used a wire snake and with a lot of wiggling it to push it through the foam was able to get it to come out through a light opening a few feet away. I then pulled a wire from there.

Some other RV's are even fiberglass insulated in the roof and that makes it easier.

[ventrman]

This may or may not help. I keep the Valves on both my Grey Water Tank and the Black Tank Closed. Of course the Grey Water Tank fills up before the Black Water Tank. At that Point, I drain first the black Water Tank, and then the Grey Water Tank to flush out the Hose. Then I close both Tanks till the next time. I also use drop ins for Odor Control. Draining the tanks more often has eliminated virtually all of the Sewer Odors.

[Charlie_D_]

Wasn't aware that Fantastic Fan had battery powered option.

OP-Adding an additional fan that does not have an existing hole in the roof would involve issues with power and where to cut. If you have the standard 12V fan it does not move a lot of air. If you do, I would replace it with a Fantastic or similar fan first.

[coolmom42]

BB_TX wrote:
If the wind is blowing in the direction from the black tank vent toward the shower vent, then yes the odor will be there. Nothing to be done about that except keep the shower vent closed.

Adding a vent fan for the shower should eliminate, or at least minimize, the odor problem. Running power thru the ceiling would be difficult. A fan large enough to move much air would probably go thru batteries fairly quickly.

This last statement is not correct. Fantastic Fans use very little power.

[jnharley]

We have a Discover America with a walk thru bath and it has a fan/vent over the shower, over the sink, and in the toilet room. Talk about over kill on fans. I would install a fan over the shower. I know our shower has a 12v light in the ceiling of the shower enclosure so there would be a 12 v power source available.

[BB_TX]

If the wind is blowing in the direction from the black tank vent toward the shower vent, then yes the odor will be there. Nothing to be done about that except keep the shower vent closed.

Adding a vent fan for the shower should eliminate, or at least minimize, the odor problem. Running power thru the ceiling would be difficult. A fan large enough to move much air would probably go thru batteries fairly quickly.