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Topic: 03 U320 Sewer Odor -- Not Admittance Valve (Read 1175 times) previous topic - next topic

03 U320 Sewer Odor -- Not Admittance Valve

Have replaced the air admittance valves and all p-traps have water.  The smell is coming from the base of the toilet when driving or when fantastic fan is running.  I took blue painter's tape and sealed around the base of the toilet as a diagnostic step and that greatly reduced the odor.

I've searched and read about this issue but haven't been able to determine if a 2003 U320 has a wax ring, a sponge rubber seal, or a rubber seal.  All three are mentioned in various posts.  Can anyone help?

Thanks!
Mark Duckworth
2003 U320 4220
Build 6199, Motorcade 17971

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #1 –
Mark,

Our coach has the Thetford Aria II toilet. I recently had to replace some of the mechanism and reset the toilet using the factory tapered rubber gasket.

Some time ago Foretravel replaced the flooring with ceramic tile and did not bother to ensure that the flange had the required 7/16"  above FFL dimension so the used some kind of generic rubber donut seal. I had to fix that problem so the factory gasket would seat properly.

Steve
Steve & Sandy
2003 U320 4220 WCDS, build#6160
Motorcade #17794
USMC '67-'71

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #2 –
Steve,

I googled the image of a Thetford Aria II and I believe it's the same as our toilet, and also our build numbers are pretty close.  Sounds like I need to pull the toilet and check the flange height in relation to the finished floor. 

Do you know if it's common for these flange seals to fail as part or normal wear and tear?  I ask to try to understand the root cause of the failure.
Mark Duckworth
2003 U320 4220
Build 6199, Motorcade 17971

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #3 –

Just got off the phone with FOT parts and Thetford customer service.  Our toilet is a Thetford Aria Deluxe 1, Model #19692.  The most likely culprit for the smells is the closet flange seal, Thetford #33239. This is a rubbery material and can deteriorate over time.  The rep said this is a flange that fits multiple toilet models.

As Steve pointed out above, the flange height needs to be adjusted depending on the height of the finished floor.  This is accomplished through the use of correct combination of 1/8" and 3/8" spacers shown in the parts diagram as items 19 and 20.  However, you'll note that the part numbers for 19 and 20 are for bulk packs of 24 each. 

The Thetford rep said to remove the toilet and check the integrity of the spacers.  They are made of the same material as the closet flange seal and can also deteriorate over time.  If the spacer(s) needs to be replaced, FOT does not have them and has never carried them according to Brad in parts.  I'll have to hunt those down.

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Mark Duckworth
2003 U320 4220
Build 6199, Motorcade 17971

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #5 –
Yeah, that's probably a good plan.  I found the spacers on Amazon.  They are Thetford #19629 but they're pricey at $34.

The new seal will be here in a couple of days and I'll wait till then to pull the toilet.
Mark Duckworth
2003 U320 4220
Build 6199, Motorcade 17971

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #6 –
replaced mine yesterday.. Havnt tested it yet. Couldnt tell any difference in the height or if it needed a spacer just replaced the gasket. didnt notice any spacers loose

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #7 –
Yes, parts for these toilets are redicoulously expensive. I've replaced everything but the curcuit board and flush switch. The next time it malfunctions it is going bye-bye and will be replaced with a manual flush model of some sort. Probably not a Thhetford ☺

Steve
Steve & Sandy
2003 U320 4220 WCDS, build#6160
Motorcade #17794
USMC '67-'71

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #8 –
Just a word of caution. Though somewhat unlikely, make VERY sure that what you smell is not your coach house batteries outgassing due to age/failure.  The smells can be similar (as can propane).

On my previous coach, the AGM batteries were in a sealed compartment (no external vent). When the AGMs began to fail, the odor appeared inside the coach several feet away from the battery location. The failed batteries were very hot to the touch. My volt meter showed no issues and the overall battery string was maintaining the normal voltage.
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #9 –
Quote from: DavidS –
replaced mine yesterday.. Havnt tested it yet. Couldnt tell any difference in the height or if it needed a spacer just replaced the gasket. didnt notice any spacers loose
Any tips or tricks on removal and reinstall?  I've replaced a number of home toilets over the years so am familiar with the basics.
Mark Duckworth
2003 U320 4220
Build 6199, Motorcade 17971

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #10 –
Quote from: AC7880 –
Just a word of caution. Though somewhat unlikely, make VERY sure that what you smell is not your coach house batteries outgassing due to age/failure.  The smells can be similar (as can propane).

On my previous coach, the AGM batteries were in a sealed compartment (no external vent). When the AGMs began to fail, the odor appeared inside the coach several feet away from the battery location. The failed batteries were very hot to the touch. My volt meter showed no issues and the overall battery string was maintaining the normal voltage.

Good tip, thanks.  I recently tried to access our house battery compartment but the compartment's screw heads are blocked by the Joey Bed rails.  I couldn't get to them with the regular square drive screwdriver.  I need to buy a square drive tip for my 1/4" ratchet. 
Mark Duckworth
2003 U320 4220
Build 6199, Motorcade 17971

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #11 –
If its the batteries you will smell it in the basement (strong sulfur). I thought my tank was smelling and turned out to be a battery.. unhooked and waited like 4 hrs and still to hot to touch with bare hands.. Smell was real bad and I could see it venting. I was affraid if I sneezed it would explode.

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #12 –
Quote from: Mark Duckworth –
Any tips or tricks on removal and reinstall?  I've replaced a number of home toilets over the years so am familiar with the basics.
Mark, you should have just 2 lag screws holding the toilet to the floor. There will be a water connection behind the toilet that may be kind if difficult to get your hand or a tool on. Then there are two wires feeding the electronics and the mechanisms.
Once the screws are removed and the water line disconnected you can move the toilet it get better access to the wires.
Then just move it to where you can work on it. The seal just slips on the outlet pipe.
For about $800 or so, you can replace all of the internal parts while you have it out☺

Steve
Steve & Sandy
2003 U320 4220 WCDS, build#6160
Motorcade #17794
USMC '67-'71

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #13 –

I got rid of my Aria Deluxe 1 in a 2001 SOB after repeatedly replacing parts due to leakage.  The final straw was when I was grilling-out and my wife yelled to me that the toilet was continually flushing on its own.  What I discovered upon removal was a leak just above the circuit board that was causing it to short out.  I replaced it with a Aqua Magic Plus after realizing the potential for the Aria to flood the coach.  I also replaced the Aria in our FT with an Aqua Magic Plus just because............

These come in high and low models, in white, bone and maybe black. 
Amazon.com: Thetford 34429 Aqua Magic Style Plus Toilet, High / White:...

I also carry one of these in case I need to do any plumbing work.  They work well, are much cheaper than Shark Bites and everything looks factory when finished.

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Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #14 –
Mark, we have the same toilet and I too have noticed that odor after driving. I have not seen any leakage around the base so have been procrastinating. But, since I have extra seals, my plan is to cut a 3/8" slice off one and glue it to another. I think that should provide adequate compression.
I thought I might have read something here on the forum suggesting this...?
Dick
Dick, '03 U320 40' Tag, 2 slides, Coach #6075
Full Timers
2009 Honda CR-V

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #15 –
Quote from: Travelin' Man –
I also carry one of these in case I need to do any plumbing work.  They work well, are much cheaper than Shark Bites and everything looks factory when finished.
Is that a PEX crimper?
Mark Duckworth
2003 U320 4220
Build 6199, Motorcade 17971

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #16 –
Quote from: Dick S –
Mark, we have the same toilet and I too have noticed that odor after driving. I have not seen any leakage around the base so have been procrastinating. But, since I have extra seals, my plan is to cut a 3/8" slice off one and glue it to another. I think that should provide adequate compression.
I thought I might have read something here on the forum suggesting this...?
Dick
Dick,

The Thetford customer service rep said it's probably just seal deterioration that is normal wear and tear.  Do what makes you happy, but you may just need a new standard height seal, not a taller one for greater compression.
Mark Duckworth
2003 U320 4220
Build 6199, Motorcade 17971

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #17 –
Just a thought if you're going to use a wax ring when reseating the toilet. Be sure you do not use excess amounts of wax. Possibly any excess can be removed through the open dump valve. The electric and manual dump valves can gum up to the point of non-function if wax falls into the tank. Don't ask me how I know this.

Jim

2002 U320 with a Microphor toilet
Jim Frerichs
2002 U320 42'

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #18 –
Rv place here said do not use the wax ring as the vibration will wear it out.. not sure but my last Rv I had to replace mine and it was a wax ring

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #19 –

How about a waxless seal.  Will conform to any condition.
John M

Sani Seal Llc BL01 Waxless Toilet Gasket - Toilet Wax Seal - Amazon.com

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John & Carm Morales

"We travel not to go anywhere, but to just go.  We travel for travel's sake.  Our great desire is to move."

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #20 –
Quote from: John Morales –
How about a waxless seal.  Will conform to any condition.
John M

Sani Seal Llc BL01 Waxless Toilet Gasket - Toilet Wax Seal - Amazon.com
Reviews not so good seems to break down.

Roland
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1993 U280 4341
2010 Jeep Liberty
The Pied Pipers

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #22 –
Got this done yesterday.  Edited the original post to correct the toilet model number. 

Nothing looked particularly bad.  There was a some build up of gunk between the closet flange and the seal.  The records that came with the coach included a receipt showing FOT replacing the closet flange seal in 2014.  The top of the closet flange was good at 7/16" AFF per Thetford's specification.

All that to say I didn't see anything that was an "ah ha!" moment.  I cleaned everything and installed the new seal.  I added a light silicone caulk layer between the closet flange and the new seal and we shall see if the odor is gone.

Edited to remove reference to hard water build up.  I think it was just sewer gunk build up because it cleaned up with soap and water.  Mineral deposits would probably have required more than soap to remove.[i]
Mark Duckworth
2003 U320 4220
Build 6199, Motorcade 17971

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #23 –
Looks like the stink problem is fixed.  Drove about an hour today and no stink at all.  ^.^d
Mark Duckworth
2003 U320 4220
Build 6199, Motorcade 17971

Re: 03 U320 Sewer Odor -- Not Admittance Valve

Reply #24 –
Mark,

If you haven't been doing this - it helps with sewer odor not to travel with windows open. Any negative pressure draws odors into the bathroom from the tank.
Jim

2002 U320
Jim Frerichs
2002 U320 42'