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Author Topic: odor while driving, negative air pressure, venting... SOLUTION???  (Read 2116 times)
viento1
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« on: June 17, 2013, 07:06:08 PM »

If I dare have my window open while someone uses the facilities, the smell is so bad my passengers all try to crawl out the window. I tried fancy vents, simple vents, lil stanker electric vents and I refuse to put nice smelling chemicals in the tank as it smells more like someone $#!% on a x-mass tree.

I believe I have the solution.

Why not install an electric waste valve directly above the holding tank. I could control the switch from the helm and keep it closed while traveling. The toilet would function normally and unless someone is peering down the hole, I do not think anyone would notice. The result would be no sewer gas in the house! The best part is I do not have to buy and maintain a dual flush toilet for $1000.

Thoughts?
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TomC
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« Reply #1 on: June 17, 2013, 07:31:21 PM »

There are chemicals that have no odor and are ecologically safe. Every chemical/holding tank toilet I've ever seen uses some sort of chemical to either mask the smell and/or speed up the break down period. Using no chemicals, of course the tank is going to smell like raw sewage-which it is. I use the old fashioned blue powder. While not perfect, it keeps the smell at bay. On warm summer days, just about have to put a packet a day in. I have a 45gal toilet tank. Might try the roof vent with venturi to take advantage of the forward motion to create a vacuum to suck out the smell. Good luck, TomC
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« Reply #2 on: June 17, 2013, 08:06:04 PM »

Hey Tom,

Always good to hear from you. I believe my bus creates a zero pressure vortex as I travel through time and space. Maybe more of a giant shop vac. Either way, the tiniest breach in any seal, p-trap, or vent results in a complete transfer of all the sewer gas into the bus.

Even myself, with my lightning fast flushing technique is no match for physics.
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bobofthenorth
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« Reply #3 on: June 17, 2013, 08:53:52 PM »

When we run into those aromatic conditions - which isn't all the time but is very unpleasant when it does happen - we open a bedroom window.  That always solves the stink.  I suppose if someone was in the bedroom they might not like that solution but nobody is so its not a problem.
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« Reply #4 on: June 18, 2013, 07:56:07 AM »

do you currently have a black tank vent going up and out the roof?

That is what I have and I added those little venturi roof vents and have no issues.

only time i ever had issue was when I was dumping black tank and my son decided to use toilet and let the gas smell from dump station into bus..
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« Reply #5 on: June 18, 2013, 12:11:28 PM »

We were gone last week on a seven day trip, I use the same old blue packets Tom C talks about, about every three days add another packet, then when I was ready to leave I checked out the dump station and there was no way my bus was going to fit so I had to wait to dump till I got home to dump about 150 miles and I had no odor issues I was pleasantly surprised this was the first time I traveled with full holding tanks, so I am a believer in the good old blue chemical FWIW.>>>>>>>>>> John.
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viento1
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« Reply #6 on: June 18, 2013, 01:21:28 PM »

I know that the magic blue stuff makes poo smell great but I prefer not to mingle my collection of nitrogen and oxygen with  anything my tank has to offer.
« Last Edit: June 18, 2013, 09:27:04 PM by viento1 » Logged

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« Reply #7 on: June 18, 2013, 02:55:33 PM »

Stop and think about it.  IF when the window is open(negative pressure) gas is allowed to enter coach. There must be an entrance point (leak)

 The permanent solution is to find the leak, a seemingly impossible task.

 One way is to drain and flush  black and grey tanks, Then seal every opening in the bus.  Go on roof with hose and fill entire system with water, where water leaks gas can leak!

 Second is a smoke test. Smoke sounds complicated but a Google search will help there or ask.

 You can play around and try this and that, but these two methods will almost always find the problem so it can be fixed permanently.
                                                                   HTH          JIm
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Bill B /bus
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« Reply #8 on: June 18, 2013, 03:13:19 PM »

Nothing really complicated as to why the smell enters the bus. According to my teaching the low pressure area at the drivers window (and obviously the door) is the lowest pressure area around the bus except directly behind the bus.
In warm weather we drive with the passenger side bedroom window cracked 6-10". Then we control the amount of air flow by varying the amount of window opening for the driver and co pilot. Sliders in both the driver and door positions. If the toilet is used and "flushed" then odor comes quickly forward as the low pressure by the forward windows is greater than the tank vent on the roof which means all the tank fumes vent into the coach until the valve is shut.

I suppose its fixable but is it worth the effort. If my bladder requires a stop then obviously I've been driving too long.

If in warm weather we ran the AC then it is not problem. We prefer the airflow to control our comfort.

Bill











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Bill & Lynn
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« Reply #9 on: June 18, 2013, 03:46:44 PM »

My simple take; If you do not use chemicals to break down the sludge and control the odor, Then enjoy your mother nature and stop crying while your buddies move away from you.   
  Grin
Dave M
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« Reply #10 on: June 18, 2013, 04:09:36 PM »

I've had serious problems with toilet odor while driving if someone uses the facilities.  I've put in tons of the odor control stuff and it doesn't help even if I put in three times the prescribed amount.  I put on a vent cover that swivels to create a venturi and it helps a lot, but not 100%.
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« Reply #11 on: June 18, 2013, 04:40:43 PM »

We add septic tank bacteria to the tank to help things along.  Another thing is to give air a chance to get into the tank.  The aerobic bacteria is much less noxious.  If by the little blue packets, you mean the stuff that contains formaldehyde, there is a problem with that.  Aside from causing problems for any septic tank you dump in, it is a pollutant. I think using it is banned in California.  If you do use it, the campground can be held responsible for the cleanup.  If they know you did it, they would probably try to come after you. 
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« Reply #12 on: June 18, 2013, 04:44:45 PM »

  In our coach, we have a ceiling vent/fan combo. with it opened a couple  inches, never had a problem. Could also run fan in "high load" situations.
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« Reply #13 on: June 18, 2013, 05:53:41 PM »

If only one air vent is open it causes suction through the path of least resistance, evidently this is the tank vent on your bus.

Always open at least two vents and the problem will go away.

I always open the roof vent if I open the front driver vent.

Or, you can open the bathroom window when you open the front vent.
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viento1
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« Reply #14 on: June 18, 2013, 09:31:13 PM »

I just ordered an electric dump valve and will install it just above the tank. It will stay closed while travelling... Will give full report.
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Don4107
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« Reply #15 on: June 18, 2013, 11:06:21 PM »

Your toilet may have an overflow prevention drain hidden under the rim.  Try filling the bowl completely to see if has one.  If you can't overflow the bowl it has a drain. It may have a built in trap that needs to fill with water to block odor. 

Even if it has a trap, it may suck odor past it with enough negative pressure. Some just silicone the hole closed. Just be aware that a leaking inlet valve can cause a overflow if you plug the drain.

Good luck
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Don 4107 Eastern Washington
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« Reply #16 on: June 19, 2013, 05:20:49 AM »

If I can keep a little water in the bowl no smell ya good luck . tried new seals lots of grease heck my wife even tried to shrink wrap it. The smell still comes up if the windows are open .

I like the elect valve idea

keep us posted 

thanks    dave
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« Reply #17 on: June 19, 2013, 11:04:08 AM »

I had the same problem when I got my 4905. Rather than put a whole lot of dollars into venturi, I took the cap off the vent and put a plastic pipe  T about six or eight inches off the roof and parallel. In fact had two vents close, put two tees upthere and have no more odor coming from the bathroom.
Larry
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gus
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« Reply #18 on: June 19, 2013, 01:08:26 PM »

One thing I forgot - sometimes when the black tank is very full and then emptied it sucks all the water out of all the traps.

Probably because the vent is smaller than the drain.

When this happens we have to fill all the traps with water again.
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Frank @ TX
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« Reply #19 on: June 19, 2013, 01:41:13 PM »

We had that problem a few years ago.  Lately I installed a household toilet.  A one piece type because I didn't want the tank vibrating loose.  I adjusted the tank level so we get about a 3/4 gallon on the half flush button and less that a gallon with the full flush.
We carry 150 gallons of fresh water and 165 gallons of waste water.
When we're at a campground we seem to dump every other day or every third day.  The washer dryer use up water.
When we're dry camping we go about a week or 10 days.
This was our solution , now you can flush any time you want.
Frank
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« Reply #20 on: June 19, 2013, 02:42:53 PM »

The craziest thing I found was not the lack tank but the gray tank, I keep my coach in mt garage / shop, ad pend about 3-4 hours a day in it, TV business work with internet quoting and keeping business going.  Point is, never use the head, just the sinks, in about a month take an exercise run around 20 miles, if I do not keep the gray tank treated well, the odor is horrible. While the black tank is clean and empty. A surprise that the gray tank was the issue.
Dave M
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Scott Bennett
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« Reply #21 on: June 19, 2013, 06:52:06 PM »

We had that problem a few years ago.  Lately I installed a household toilet.  A one piece type because I didn't want the tank vibrating loose.  I adjusted the tank level so we get about a 3/4 gallon on the half flush button and less that a gallon with the full flush.
We carry 150 gallons of fresh water and 165 gallons of waste water.
When we're at a campground we seem to dump every other day or every third day.  The washer dryer use up water.
When we're dry camping we go about a week or 10 days.
This was our solution , now you can flush any time you want.
Frank

Since we're on the subject of poo control, I have been considering putting a house toilet in our next coach. We love our current Dometic porcelain, but I wouldn't mind a house toilet if we could get the flush to use little water. Can you post some photos of yours please? I don't think anyone will object...after all, a throne by any other name, is still a throne  Wink
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Scott & Heather
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« Reply #22 on: June 21, 2013, 06:36:12 AM »

Hi Scott,
I've never been able to post photos to the board.
We have a "Glacier Bay " one piece , this is a Home Depot brand.
Our tank is right below , so the water is used to clear the bowl not to carry the waste thru the piping.  Because of this I was able to adjust the water use quite low in both the half flush and the full flush.  Hope this helps.
I you still want a photo I can email you one.
Post your email address and I'll sent you a photo.
Frank
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