Black Tank Odor When Using Bathroom Vent Fan

[bradsr63]

We get an odor, sewer smell, every time when use our exhaust/vent fan in the bathroom. I use the recommended amount of chemical and flush it out after dumping. The smell is not there when the fan isn't running. We try to run the fan only when using the shower to get the moisture out. I don't believe the amount of moisture, that taking showers create, is good for the bathroom walls, etc. and want to use the fan, but the smell is disgusting. I did have to change the water valve module and had the toilet off before using the camper. I followed the instructions and installed the new seal that came with the kit and tightened the bolts as stated. I have no water leaks, but do have the odor. We just bought the camper and only used it once, before needing to replace the water valve module. This past weekend I added double the amount of tank deodorizer to see if this will help. Does anyone have any info. on this problem?

[3'senough]

Originally Posted by bradsr63

We get an odor, sewer smell, every time when use our exhaust/vent fan in the bathroom. I use the recommended amount of chemical and flush it out after dumping. The smell is not there when the fan isn't running. We try to run the fan only when using the shower to get the moisture out. I don't believe the amount of moisture, that taking showers create, is good for the bathroom walls, etc. and want to use the fan, but the smell is disgusting. I did have to change the water valve module and had the toilet off before using the camper. I followed the instructions and installed the new seal that came with the kit and tightened the bolts as stated. I have no water leaks, but do have the odor. We just bought the camper and only used it once, before needing to replace the water valve module. This past weekend I added double the amount of tank deodorizer to see if this will help. Does anyone have any info. on this problem?

There's not much you can do except scrub the tank out. I usually do a good flush when in FS campsites. I have found that when in route to your CG dump a capfull of Laundry Det or DW soap into the tank with a citrus based deodorizer works best. I am sold on the TST orange right now. This is by far the best stuff that I have ever used whether in boats or RV's. The key is to have about 2-3 gallons sloshing around in your tank to help break down the sludge and get up on the walls.

Since your unit is used and you have no history or tank health I would do the above while in transit then when you get to the site, hook up and dump a 5 gallon pail of hot water down the bowl with the gate open. This will get rid of most of the solids that may be stuck to the bottom of the tank. Then I would close the gate and dump another bucket of hot water down there to sit for an hour. After that flush it good and treat with 2 gallons of water and some treatment. You need to have some water in the tank for the best results. Once you get your tank health back you should see a considerable difference in odor reduction while the fan is on. Keep in mind that if you flush while the fan is on some odor will come back in due to pressure.

Hope this helps.

[bradsr63]

Thanks for the advice. I bought a cheap stick type black tank flusher from our CG that has to be used by putting it down the toilet and running an extra long hose to reach inside the camper, but I'm not happy with the procedure. I've used it, but it doesn't seem to have enough force behind the spray to loosen anything deposits up in the tank. Camping World sells a similiar item with a brass spray nozzle that rotates, but I'm not sure it would be any better. They also have one that installs inside the tank with a hook up to the outside that could be placed by the dump valve handles. It's not that expensive, but cutting a hole in the black tank could cause other problems. I will try your method and see how it works for me.

[RedHorse1]

Since you get the smell when the fan is running I suspect the toilet valve is not sealing completely. Lower pressure in the bath pulling "vapors" from the black tank.

[TX_Arvee]

Do you keep some water in the toilet bowl between flushes? I keep a few inches in there. If you are getting fumes in while running the fan and the bowl has water in it (and it holds that water) there is no seal leak there and fumes are not coming from there. Now, if you are running the fan and flush the toilet, it IS going to suck some fumes into the bathroom while the gate is open to the strink tank. there isnt going to be a way around that, it's normal. Best to not run fan when flushing if you dont like the smell.

[bradsr63]

I do keep water in the bowl and the seal seems to be holding the water ok. I will have to check to see if water seeps out over time, but every time I open the lid there has been water in the bowl. The odor is really noticeable only when trying to run the fan when taking a shower. We don't run it when using the toilet.

[rheyco]

the toilet is not sealed properly from the repair it will leak fumes and not leak water you need to reseat the toilet.

[3'senough]

Few things you might check and help you widdle down the culprit.
1. Without the fan on, tank empty but treated, open the flush valve. Do you smell excessive odors? Mine I cannot due to it being clean. Clean the tank then try again.
2. With water in the bowl and fan on do you smell the odors?
3. Check under your cabinet and see if there is a airlock vent stack off the black drain pipe. Is there an odor there with the fan on?
This is commonly used in the grey plumbing systems since they are cheaper and easier to run than stacks through the roof.
If it's not working and you are hooked up to a sewer line the fan will pull the odors from the cesspool line outside the unit with your grey valve open. You could close your grey line a see if it goes away.
4. If none of the above the stink is coming in from around the bowl and you need to try to tighten your bowl if any play is present or maybe replace the seal as mentioned above.

There are several places odors can stem from especially with the draw that the fan creates. Start with tank IMHO.

[TX_Arvee]

If you have one of these under your sink, I bet your fan can pull gases from your grey tank. My grey tank has smelled nastier than the black tank at times. It is a very weak sealing device (i guess by design). I have one on the kitchen sink and it at times will burp nasty smelling gases into the cabinet. It is secondary to a roof vent also on the sink, so I wonder why it is even installed. I unscrewed it and examined it to see how it works, once off gases really came through the pipe...could it be you have this and the fan is pulling gases out here?

[Camping Couple]

Originally Posted by bradsr63

Thanks for the advice. I bought a cheap stick type black tank flusher from our CG that has to be used by putting it down the toilet and running an extra long hose to reach inside the camper, but I'm not happy with the procedure. I've used it, but it doesn't seem to have enough force behind the spray to loosen anything deposits up in the tank. Camping World sells a similiar item with a brass spray nozzle that rotates, but I'm not sure it would be any better. They also have one that installs inside the tank with a hook up to the outside that could be placed by the dump valve handles. It's not that expensive, but cutting a hole in the black tank could cause other problems. I will try your method and see how it works for me.

We bought the flexible flush stick with the spinning sprayer at the end of it. We used it on our 17 ex-port before we sold it last month as the buyer was really concerned wih the tank being cleaned. We used it in conjunction with laundry soap. I used an inspection camera used by plumbers to inspect sewer drain pipes....(I work for a mechanical contractor), to show the buyer the interior of the tank. It looked like a new tank! So the sprayer works.

[tlhdoc]

A few thoughts and ideas. The grey water tank may be your culprit. Have you used anything in the grey tank? In the black tank I add some Calgon water softner. Soft water makes it harder for "gunk" to stick to the sides of the tank. You could also try adding some to the grey tank. If the black tank is the problem dump a bag of ice cubes into the tank and take it for a ride. The ice will knock around in the tank and dislodge anything that is sticking to the walls of the tank. I also have one of the sticks, and it seems to work pretty well. I do this when the dumpstation is not busy. I dump the tanks. After they are both empty, I close the valve on the grey tank, disconnect the sewer hose from the sewer and use the running water to fill the hose/back flush the black tank. If you hold the end of the hose up higher than the tank, the tank will fill this way. Then put the sewer hose down and let the tank drain again. As long as I see any particles coming out I keep repeating the process. Once the black tank is clean I close the valve for it then open the grey water valve and repeat the process. I have had some nasty stuff come out of my grey water tank. Good luck.

[jdorant]

I second that the grey water tank could be your problem. I put powder calgon (water softener) and powdered tide in both my tanks to keep them clean. And a little lemon pin-sol in the black for the smell. Works pretty good.

For the Black tank, I was thinking of getting one of these.
http://www.amazon.com/Valterra-F02-4...=IPRRZJNN8OJNA

[tinlizzie23]

Another formula for cleaning your tanks came from another camper on this forum a while back. Seems to work very well for us. No odors at all. In a gallon plastic jug put together 8oz pine-sol, 8oz liquid fabric softener, 8oz household ammonia, and 8oz baking soda. Mix with a quart or so of water, then fill the gallon jug the rest of the way with more water. Mix, then pour about a cup down each drain (sink, lavatory, and whatever else you have), then pour the rest of the gallon into the toilet. Follow with 2-3 gal of water. If really dirty, add 20lb ice cubes and take a 1/2 hour ride and dump. I put this concoction in every time I dump, and never have any odors from any of my 3 tanks.

[TCNashville]

Hey Brad & Family, I had the exact same problem in the first camper I bought. I know the post is somewhat old and I hope you have the problem fixed by now but if you don't, here's what I found out. After 2 new seals and even a new toilet didn't cure the problem, I eventually looked at the black plastic ring that's screwed to the floor that the toilet bolts to. I found that 2 of the 4 screws were stripped out, so when I tightened the toilet down, it actually lifted the ring allowing odor to escape. The smell only happened when the fan was pulling the air out. It was an easy fix as I drilled new holes, not interfering with the seal contact and allowing the screws to seat.

[Roy W.]

I don't believe your holding tank(s) are at fault. The problem is you need to have a window or another roof vent open when using the bathroom fan. What is happening is that when the fan is on, it is drawing outside air through the holding tank vent stack on the roof, through the holding tank, and up through the toilet. Try opening a window when you turn the bathroom vent fan on and see if it changes anything.

[Spike99]

Originally Posted by Roy W.

I don't believe your holding tank(s) are at fault. The problem is you need to have a window or another roof vent open when using the bathroom fan. What is happening is that when the fan is on, it is drawing outside air through the holding tank vent stack on the roof, through the holding tank, and up through the toilet. Try opening a window when you turn the bathroom vent fan on and see if it changes anything.

Agree....

Two different 3rd party products will dramatically eliminate smells in the bathroom. They are:

If getting smells within the RV/Chassis during towing, simply install the 360 Roof Top product. This product's design creates a negative air pressure above the vent pipe. Thus, "sucking" the bad air up and out the vent pipe. If wondering, normal vent caps don't create upward suction power. And sometimes, normal factory vents push air "down" the vent pipe while towing. Thus, pushing bad smells down (into) the tank and since air must come out, the bad air goes into into the RV's chassis. Many times, I read the 360 siphon vent Product works great. Especially during towing (that makes wind - to create this upward suction). And, works great when camping on windy days as well. For more details, surf: https://360productsnorthamerica.com/site/more-info

If getting smells within the chassis on "no wind" situations, I read many time the Power Fan vent products works great. They can be either solar power, 12V power or even 110/120V power. I like the idea of solar power product (such as: http://www.etrailer.com/Enclosed-Tra...53-945001.html ) but I read it sometimes has clicking sounds. And, it doesn't work well on NO sun days. Thus, I like the 12V or 110/120V power fan products (such as: http://www.lslproducts.net/IL-DSPage.html ) much better. Especailly with their manual off, low and high speed switches.

If one cannot install the "inline"12V or 110/120V product (re: http://www.lslproducts.net/IL-DSPage.html ) in one's RV, then perhaps one can create their own roof top Power vent product. This is done using some PVC or ABS piping, a properly physical size 12V computer fan, some screen (to keep the bugs out) and some white paint. For a power had product that I created for my seasonal site Jayco 29FBS, surf: http://i178.photobucket.com/albums/w...hProduct-2.jpg

Hope this helps others...

[Spike99]

.

I forgot to mention that a "store bought" vent fan WAS available from http://www.lslproducts.net/ company. Unfortunately, they stopped making this specific product 2 years ago. But, using its design and historical installed pictures might allow you to find a simular store bought product. Or, make your own product using simple store bought PVC / ABS parts. For example, 12V 38 CFM computer fan and an extra large RV vent cover and some plastic piping. For more details of their previous product, surf: http://www.modmyrv.com/2008/10/02/rv...dor-controller

Hope this helps as well...

[BlueHaul]

I also do as tinlizzie23 says and dump 20 pounds of ice down there once in a while before pulling out of a site. With a few inches of water at the bottom of the black tank, the ice seems to "scrub" the walls pretty clean as you drive. Great thought also about the air lock in the cabinet! Who knows what previous owners put down the sinks - may as well clean the grey tank out as well.

[CookieMonster]

We have a brand new, 2012 Pinnacle.. been experiencing the same problem, both with the exhaust fan in the toilet area, and with the big exhaust fan on the roof (run by the thermostat). Am baffled, as everything is new, treating the tanks appropriately (I think), etc.

At one point, I even reglued (put more glue around the pipe connections) the ABS (black pipe) permanent connections under the sinks... which actually did seem to help (one of them had water seeping out of it on some occasions, so did have one issue for sure, under the bedroom area sink) ... as well as hand tightened, snugged up all the threaded connections.

Appreciating the hints, suggestions here on the forum, about other things to watch check... for now, we just minimize the use of the exhaust fans, as every time we turn them on, and leave them on for any length of time, we get black/gray tank (not sure which one it is coming from) odor.