Lets Talk Toilets, Maby Marine?

On my Winnebago Voyage like most other class A motor homes the toilet dumps straight down into the black tank. I have checked the vent and all other areas but still get that WONDERFUL smell every time I flush. I have tried all the deodorant tricks. If you have ever had a water trap in your home dry up you can understand the problem. Our home toilets use a water trap so why not in the RV.  Or a hand pump type like in boats. Has anyone beat this problem? Thanks Stinky in Mobile!

Just the use of chemicals could very well be the cause of your problem.  Many of us use no chemicals at all.  If you have used anything containing formaldehyde it may take some time to recover from the damage that has caused.

You shouldn't get any odor from the black tank unless the vent is blocked or has slipped down into the holding tank.  Another possibility is if you run an exhaust fan in the bathroom it can draw air up from the tank when flushing.

My plan was to not use any chemicals at first but then the smell got so bad I tried chemicals with no results. I also make sure the vent fan is not on when I flush. I even try to let a large amount of water go in the tank from the toilet to start a rush of air out the vent to act as a tuned pipe to create a vacuum on the bowl end but still STINKY! I sure would like a water trap type toilet. I may try that vent fan that mounts on the roof to keep a vacuum on the tank, but that would be one more thing to do maintenance on. Thanks for your suggestions.

I think Ned hit the nail on the head.  You shouldn't get those fumes when you flush unless you are not receiving proper venting.

We use enough holding tank chemical for 80 gals of capacity of the old fashioned blue chemical (two servings, so to speak).  If you are using the new orange enviromental blah blah blah chemical....it flat does not work.

I also agree with the fan...if its running, and you flush....the odor will come right up in your face!

I believe the old blue colored chemical contains formaldehyde and formaldehyde is one of the best preservatives known.  Now why would anybody want to preserve the contents of their black water tank??? ??? ???  There are many products available that do not contain formaldehyde.  The black water tank works similar to a septic system and bacteria is required for it to work properly formaldehyde kills bacteria destroying the natural action and can/will cause odor problems.    Since this problem started when they were using no chemicals it is very likely a vent pipe problem, either the vent pipe is too low into the tank or plugged.  I do know of one case where the vent pipe was found to have some kind of nest in it possibly mud dabbers. 

Ron:

I think?  FrontrangeRVer may be using the same thing we use.  We buy Thetford's "Campa-Chem" at WalMart.  It is a blue powder that comes in foil envelopes and the box states "Formaldehyde Free".  It seems to work pretty well.

It is probably OK as long as it does not contain formaldehyde.

Oh my gosh Art - a marine head?    You have managed to bring back many unpleasant memories of me tearing apart heads to rebuild the pumps and in some cases removing the discharge hose because of crud coating the inside walls.  Many times I had to whack the hose against a piling to shake the crud loose.  I spent hundreds of dollars looking for the 'perfect' marine head - the closest I came was an electric Crown - it had a huge macerator that could chew up a turkey drumstick and spit out tiny pieces  .  It was a good thing we had two heads on the boat because frequently one was down for maintenance.

I want nothing to do with marine heads (can you tell  ;D?)  It is an absolute joy to have a head where the discharge is straight into the tank.

Ned and Mark I think are on-target - with good tank ventilation and not running your exhaust fan, you shouldn't have odor problems.  We very rarely  ever use any tank chemicals.  I personally have not seen the need for them.

At an FMCA seminar I attended a few years ago, the head chemist for Thetford gave a presentation about RV sanitation and made a point of mentioning that formaldehyde is not normally deleterious to septic systems - she said the typical campground septic problems are caused by grossly undersized septic systems.  Normal residential sizing is by number in the household and then a tank of so many gallons and a drain field of X number of square feet is specified.  The assumption is the input to the system is more or less gradual and over a 16 hour period.

That design criteria don't work for campgrounds - in this case you might have 10-50 campers dumping 20-100 gallons each and then the septic system gets a huge surge that it cannot handle.

John Canfield said:

At an FMCA seminar I attended a few years ago, the head chemist for Thetford gave a presentation about RV sanitation and made a point of mentioning that formaldehyde is not normally deleterious to septic systems - she said the typical campground septic problems are caused by grossly undersized septic systems.  Normal residential sizing is by number in the household and then a tank of so many gallons and a drain field of X number of square feet is specified.  The assumption is the input to the system is more or less gradual and over a 16 hour period.

That design criteria don't work for campgrounds - in this case you might have 10-50 campers dumping 20-100 gallons each and then the septic system gets a huge surge that it cannot handle.

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That is about what I would expect from Thetford and IMHO it is a bunch of bull.  I also question the integrity of any company that sells a product that preserves the contents of the BWT and then tell us oh thats ok.

Ron - you're too cynical 

John Canfield said:

Ron - you're too cynical 

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But fact is fact. ;D

Two things to check/remember.  Never never have the close by overhead exhaust fan running when you flush. Also, in an older Class C we used to have there were overflow holes in the toilet bowl itself.  They were up under and around the bowl where you could not see them. We had to get some rubber plugs and close off these holes to eliminate smell.
JerryF

I just had a thought:  What if you poured a couple of caps full of cooking oil in the black water tank (gray too for that matter)?  Wouldn't that float on top of the water providing a seal that would trap the odor beneath?

George - yeah - that might work.  I've heard of people floating I think mineral oil on top of battery acid.  Only issue might be a film that collects on the side of the tank that might inhibit the tank sensors.  Mine are pretty persnickety as is!

Once in a while I pour a little (1/8 cup or so) vegetable oil into the toilet bowl for a little lube.  I used to do that for my marine heads.

Campa Chem does contain formaldehyde - just like Aqua Chem, according to the MSDS safety sheets.

Whether you use chemicals or not, adding several gallons of water before you use the black water tank will greatly aid the tank's functioning. Just fill the toilet to the brim and flush 4-5 times, or until you can see some water underneath the toilet outlet.

If you're using a chemical, this fills the outlet piping and lets the chemical disperse throughout the tank instead of just concentrating at the dump valve.

Without chemicals, a layer of water on the bottom of the tank allows the solids and toilet paper to dissolve by the time you're ready to dump.

I haven't used chemicals for years and rarely if ever have an odor problem.  If you have been using formaldehyde based chemicals, stopping WILL cause odors until you've dumped a couple of times and flushed all of the bacteria-killing formaldehydes out of the system.   

George

Many of us here don't use anything in our BWTs. As far I can tell, any odors that do come from the tank vent out the top vent and we don't smell anything. Not sure what is to be gained from the old, other than greasy doo-doo ;D

I've used a product called "Happy Camper" for four years and have been totally "happy" with the results.
I was camping at Shasta Lake, CA for a few days and ran across the creator of this product. There are several fleets of house boats on the lake and they all use this product. In the summer it can get really hot in that area and black tanks were a huge problem for them with all of the party goers.
I Don't use anything else. Happy Camper is an enzyme type product and I always buy it at the large rallies; FMCA, Quartsite and the like. The cost is minimal. If you try it, it will take tow dumps to remove the residuals and clean the tank.

Art In Mobile said:

On my Winnebago Voyage like most other class A motor homes the toilet dumps straight down into the black tank. I have checked the vent and all other areas but still get that WONDERFUL smell every time I flush. I have tried all the deodorant tricks. If you have ever had a water trap in your home dry up you can understand the problem. Our home toilets use a water trap so why not in the RV.

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RVs *DO* have traps, and particularly Sealand Toilets used in Winnebagos! Failure to service this trap is a rather common source of toilet odours.

As you might guess, the channel leading from the overflow outlets, lead straight into the black tank. There is a trap betweem in that outlet and the tank that must be serviced by filling it with water, to prevent black tank odours from venting to the bathroom.

Our Concerto toilet goes straight down.  Once in a while we will get that "oh my gosh-what's that smell" in the coach, and in every case it has been the washer/dryer drain trap that apparently has lost its water.  I tell Jane to do a load of clothes and problem solved  8)