Sewer Odor, roof sewer vent, air admitance valves inside...

Topic: Sewer Odor, roof sewer vent, air admitance valves inside... (Read 2422 times) previous topic - next topic

Sewer Odor, roof sewer vent, air admitance valves inside...

May 14, 2018, 11:06:43 pm

Sorry for length, but full description needed to explain what I see and for questions.

We have 50 amp electric and water, no sewer connection in present location. 96 degree highs to "cook" the sewer tanks. I can't flush tanks presently with no sewer connection.

Using bathroom vent roof fan on exhaust, no matter low, middle, high speeds, with 2 windows cracked 1/2 " to 1" each, with or without air cons running, exhaust fan sucks in unpleasant odors (stronger when fan speed higher). No odors outside the exterior of the coach at ground level are noticeable. No sewer leaks noticeable in basement either side or under coach. I have smelled this odor on occasion before while driving with windows and or roof vent in certain configurations.

I have a blue colored sewer bacterial breakdown treatment (stong smelling in the bottle, bottle long gone to trash) in the black tank with a distinctive odor. The odor while running the roof vent has that distinctive blue treatment smell, thus I think I am getting black tank, not grey tank odor (but am not positive).

On the roof, there is only one sewer vent (not two as in my previous coaches). *******"Either" only the black tank vents to roof, or "more likely" black and grey vents merge out of my sight from both inside and in the basement.******

From outside passenger side, removing the grey carpeted panel that covers the water manifolds, I can see the black vent go up into the coach interior, and grey tank vent do the same (seperatly). They do not merge in the basement.

There is only one vent on the roof. I can view from inside the coach at ceiling level, by opening the pantry doors right next to the fridge, one vent pipe going up to roof. Only one vent pipe can be seen heading through interior ceiling to roof.

I can not see the vent pipe(s) any lower from the interior of coach - pulling out the 3 pantry cabinet slides by the fridge reveals only a wooden back wall.

**If** the 2 basement vent pipes (grey/black) merge, it is out of sight without easy or reasonable accessibility.
Note: I cannot imagine that the gray tank does not merge to vent to roof with the black tank? "Only air admittance vlaves for grey tank does not seem reasonable??

***If*** the two vent pipes merge inside out of sight, then the air admittance valves if defective, could emit black tank odor (as well) instead of only grey tank odor. (agree??)

So question one: anyone know for sure if black and grey vents merge behind back pantry wall to lead to roof with only one roof vent?

Coach layout: Kitchen sink passenger side, washer / drier passenger side. Bath sink and shower drivers side.

I have found three total air admitance valves (AAV) "thus far": one in clothes hamper directly behind the accuflush toilet, near shower (I am "guessing this one is for shower drain), one under the bath sink and clearly for bath sink P trap, and one I can see shining a flashlight behind right side of washer drier (nearly cetrainly for washer drain, **possibly** "also" for kitchen P trap.

Ths far I do not see a 4th air vlave for kitchen sink, could be hidden out of sight. I can visually check the AAV in the clothes hamper behind the accuflush toilet - pulled the top cap off and rubber valve works fine (sealed, pulls down ok).

I can see but not access the bath sink AAV - buried deep behind sink bowel and cabinets. I can see the washer drier one, but will have to pull out the washer to get to it.

Using my nose, I "think" the odor is coming from the washer/drier area, not clothes hamper nor bath sink canbinet. And toilet is sealed at the valve and holds water, so nearly positive no odor pulled in there.

The sink and shower P traps have water in them, no odor coming out of drains. I added around 2 gallons of water to washer, then hit drain cycle to add water in case odor coming through washer drain.

At this point, I think I need to change the AAV behind the washer first?
Question: is it "screw in" Unthread old, thread in new? 1.5 inch?

I sure wish I knew for 100% if grey and black vent pipes merge behind the back pantry wall out of sight.. Then I would know if the air admittance valves could emit black tank odor when exhast fan sucks odors in (past a defective AAV).

I am also thinking or replacing the current roof top air vent (in picture attached) with this type "cyclone" roof vent: Cyclone Sewer Vent - Camco 40595 - Sewer Accessories - Camping World

Edit: I found a 4th air admittance valve behind the kitchen drawers (for the kitchen sink P trap). No odor noticable in the area.

More likely than ever the washer drier AAV is defective, but still I question how grey tank vents to roof (has to merge with black tank vent out of sight behind pantry)

??

Editing top post for clarity:
The one roof vent serves both grey and black tank. Post further down on how I verified.

The AAV in hamper behind the toilet is for the shower - verified. Two AAvs behind washer - both for washer. One behind bath sink bowel, one behind kitchen drawers.

The "turbo turd" toilet does not have a AAV.

AAvs are 1.5 inch threaded. Unscrew old, teflon tape new and screw in. May need channel lock pliers to get old ones loose.

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #1 – May 14, 2018, 11:13:39 pm

I found a 4th air admittance valve behind the kitchen drawers (for the kitchen sink P trap). No odor noticeable in the area.

More likely than ever the washer drier AAV is defective, but still I question how grey tank vents to roof (has to merge with black tank vent out of sight behind pantry)

??

More info: Pulling the bottom pantry drawer out did not help as I could not remove the "floor" to look and see if the 2 vent pipes merge. From outside, removing the fridge outside access panel I could look rear ward and see one vent pipe rising to roof level, but view downwards was blocked to see if they merge near floor level. I have zero plans to pull the residential fridge to look behind and sideways for merging vent pipes.

I may use a bore scope type device I have for a cell phone to look behind and sideways from the outside fridge access door sometime in the next week or two. We move on Wednesday, so that will wait along with pulling the washer to access the washer co-located air admittance valve. In the meantime we will use the roof vent sparingly or with windows wide open.

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #2 – May 14, 2018, 11:57:36 pm

I have kitchen/washer-dryer on drivers side. Lav in the middle. Toilet and shower on passenger side. I have two rooftop vents that I just replaced today with the Camco weather vane model. Easy install other than my vent pipes didn't protrude from the roof very far so had to put the screws very close to the end of the Camco white tube.

I also replaced all my AAV's last fall and they were all screw in 1.5". I bought new ones at Home Depot. I believe (I could be daft though) that on my coach the shower and W/D AAV are linked.

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #3 – May 15, 2018, 12:02:04 am

To test if it's the "air admittance valve" put a plastic bag over it with a rubber band to seal it and turn on fan. If odor goes away that's it.

Keith

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #4 – May 15, 2018, 12:08:14 am

Dan, I think your nose knows( pun intended). I would change the W/D AAV first.
Kieth has a great idea!

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #5 – May 15, 2018, 12:57:03 am

Quote from: Keith and Joyce – May 15, 2018, 12:02:04 am

To test if it's the "air admittance valve" put a plastic bag over it with a rubber band to seal it and turn on fan. If odor goes away that's it.

Keith

If I could reach it without emptying cabinets, taking 2 doors off the washer cabinet, unhooking washer hoses, and pulling it all the way out I would try that.

With all that labor, I'll replace it for sure when I pull washer out. Looking at this one and ordering 3 (the three I can get to): Amazon.com: Oatey 39012 ABS In-Line Vent 2X2 13/16: OATEY: Home Improvement

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #6 – May 15, 2018, 01:02:43 am

I still find it strange there is only one roof top vent. Anyone else have only one roof top sewer vent and not two? The grey and black vent pipes HAVE to merge out of my sight and reach, right?

Do I just grab the air admitance valve with water pump /ratchet pilers and turn vigorously to get the old one out? The one under the bath sink looks like I would have to pull the sink bowel to get to. The other 3 I think I can get to with some dissambley of the coach.

I'm going to order a cyclone vent for the roof while I'm doiing all this. Cyclone Sewer Vent - Camco 40595 - Sewer Accessories - Camping World

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #7 – May 15, 2018, 01:21:05 am

AC7880, I've had both, this one pulls more air, lower, and no moving parts:
360 Siphon RV Vent Cap, White - Lippert Components Inc 389381/364466 - Sewer...

360 use to make the cyclone, the 360 siphon was better and they sold off the cyclone.

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #8 – May 15, 2018, 01:54:01 am

I found 2 older threads that add information to my quest:

Air Admittance Valves, aka "Stinky Coach Syndrome"

Pepe le Pew aroma solved

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #9 – May 15, 2018, 11:15:08 am

Dan, like you I have a '03 and only one OEM stink-pipe coming through the roof.

When we were at Xtreme having the roof re-done I mentioned to Greg about the vent cap being yellowed from age. He said, "No problem." and produced a new OEM cover for about $12.00, so they must keep them in stock.

I have no unpleasant odors with just one stink-pipe. If it was me I'd buy a couple of simple/good quality AAVs, replace the one(s) behind the Splendide and not worry about two into one stink-pipe.

When I built our S&B 25 years ago I used AAVs at every fixture and also any power vents (with the exception of the down-draft range and downstairs bath that vent through the second floor band) are released into the attic, then out through the ridge vent. Consequently there's nothing potruding through the roof except a fireplace chimney. I have never had to replace a single AAV, and we've never noticed any unpleasant odors. That type of construction is prohibited in Massachusetts and has been for decades.

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #10 – May 15, 2018, 12:08:23 pm

Dan, we have an '03 and only one vent pipe coming out the roof. Might be the placement of the toilet that determines how many vents there are.

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #11 – May 15, 2018, 08:18:22 pm

Our 03 only had one vent pipe through the roof also.

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #12 – May 16, 2018, 12:13:42 am

Anyone confirmed whether that one roof vent is black tank only, grey tank only, or a merged vent for both? I'll try a bore scope later this week or next week to see if they merge. I know behind the water manifold in the basement two pipes extend from top of the two tanks up into the coach.

Moving day tomorrow. I'll be buying the new air admittance valves in a couple of days and pulling the washer to get to the 2 behind it.

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #13 – May 16, 2018, 06:59:49 am

Quote from: AC7880 – May 16, 2018, 12:13:42 am

Anyone confirmed whether that one roof vent is black tank only, grey tank only, or a merged vent for both?

Dan,
On our '97 the 2 merge inside the side wall of our washer/dryer cabinet and only one exits the roof. Also there is an an AAV hid in that wall space. This is where I started using the better quality AAV 39017 - Oatey 39017 - 20 DFU Sure-Vent Air Admittance Valve w/ 1 1/2" x 2"... than the $4 no name brand at the home improvement store.

Mike

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #14 – May 16, 2018, 11:57:53 am

Quote from: Pamela & Mike – May 16, 2018, 06:59:49 am

Dan,
On our '97 the 2 merge inside the side wall of our washer/dryer cabinet and only one exits the roof. Also there is an an AAV hid in that wall space. This is where I started using the better quality AAV 39017 - Oatey 39017 - 20 DFU Sure-Vent Air Admittance Valve w/ 1 1/2" x 2"... than the $4 no name brand at the home improvement store.

Mike

Thanks for the info. I don't believe I will have room for the larger/better AAV behind the washer. I can see one of the two back there looking down the side of the washer with a flashlight. Looks very tight for space.

I'm tempted to buy some of each, as I know I will have room in 2 other locations for the better one. Then I'll do washer location first.

My vent pipe(s) are hidden from view with even some disassembly. I'll try the borescope to check within the week. I guess I could also first dump both tanks, then run a water hose into the roof vent, and see which (or both) sewer tanks fill.

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #15 – May 16, 2018, 12:10:52 pm

I have an 02 U320.. I found the vent under the sink in the bathroom and one under the sink in the kitchen.. Looking in the closet I dont see a way of getting the back wood panel off. any tricks? Looking from behind the drawers in the bedroom I cant see the other valves.. can anyone confirm where they are (shower and washer)?. Confirm how to get to it.. There is non behind the toilet for sure so not sure where else to look.. I also have 1 single vent on top.

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #16 – May 16, 2018, 12:38:04 pm

Quote from: DavidS – May 16, 2018, 12:10:52 pm

I have an 02 U320.. I found the vent under the sink in the bathroom and one under the sink in the kitchen.. Looking in the closet I dont see a way of getting the back wood panel off. any tricks? Looking from behind the drawers in the bedroom I cant see the other valves.. can anyone confirm where they are (shower and washer)?. Confirm how to get to it.. There is non behind the toilet for sure so not sure where else to look.. I also have 1 single vent on top.

On my coach, a 40' tag U320, one AAV is hidden up behind the bath sink bowel. Pulling out top drawer next to it gives "some" access. The kitchen sink # 2 AAV I can see by pulling some of the kitchen drawers out and looking behind. In the clothes hamper immediately behind the "turbo turd" toilet is #3 AAV, possibly for the toilet, possibly for the shower instead..

Behind the washer are two. One for washer, one "maybe" for the shower drain (though shower is cross coach so I could wrong on this) . To change these two I'll remove everything from top cabinet to get to the washer water hoses and power plug, take doors of washer closet for working space, pull the washer out into "hallway". While the washer is out I will clean the drier vent thoroughly.

The 5th AAV (the extra one behind the washer), "could" vent one of the sewer tanks (grey most likely) instead of a specific item on the interior of coach. I'll try and figure out /verify all the above when I get parts and do the work. I'll follow up here when I do.

5 total AAVs on our coach.

Question: Is your toilet a direct drop into the sewage tank, or a electric pump model? That may determine if a extra AAV is present.

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #17 – May 16, 2018, 12:58:57 pm

Hello Dan, This will be a lengthy post also. I just read your original post. If my post helps anyone with a similar situation it will be worth it. The odor you talk about reminds me of an event over ten years ago. I just bought an rv with a leaking seal around the interior bowl valve the dumped the water to the black tank. With this leak, the bowl would not hold water. We were driving from AZ to Oregon. When driving, the odor became unbearable. My wife said if I did not get the odor issue fixed, she was flying home, not driving home. I called my tech at home and asked what to do. First I tried silicon grease on the ball valve, that was not enough. SECOND suggestion and what worked. Bought a product called Happy Camper Amazon.com: Happy Campers Organic RV Holding Tank Treatment - 64 treatments:...
Filled black tank with water and added double the amount of happy camper, stored 25 hrs and dumped. Next added a few gallons of water and proper amount of Happy Camper. Odor was gone. This product does not cover up odors, it eliminates them. If you try, let me know what you think. I have used only this product for over 10 years with very clean tanks as a result.

I use it in both my grey and black tank.

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Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #18 – May 16, 2018, 07:19:17 pm

Most of the time we use only water in the sewer tanks. Sometimes some laundry soap and fabric softener.

We have used the happy camper product in the past as well for a "deep clean", and it worked fine (bacterial action I think). The current odor problem is 100 percent the exhaust fan dragging in odor past the air admittance valve behind the washer. It didn't help that we were camped in 96 degree weather with no sewer connection.

I back flushed the black tank 4 times today using the grey water (lifting sewer hose method). Tanks pretty clean now, and next 2 weeks are full hookups till I get the AAVs switched out behind the washer.

Quote from: Jack Lewis – May 16, 2018, 12:58:57 pm

Hello Dan, This will be a lengthy post also. I just read your original post. If my post helps anyone with a similar situation it will be worth it. The odor you talk about reminds me of an event over ten years ago. I just bought an rv with a leaking seal around the interior bowl valve the dumped the water to the black tank. With this leak, the bowl would not hold water. We were driving from AZ to Oregon. When driving, the odor became unbearable. My wife said if I did not get the odor issue fixed, she was flying home, not driving home. I called my tech at home and asked what to do. First I tried silicon grease on the ball valve, that was not enough. SECOND suggestion and what worked. Bought a product called Happy Camper Amazon.com: Happy Campers Organic RV Holding Tank Treatment - 64 treatments:...
Filled black tank with water and added double the amount of happy camper, stored 25 hrs and dumped. Next added a few gallons of water and proper amount of Happy Camper. Odor was gone. This product does not cover up odors, it eliminates them. If you try, let me know what you think. I have used only this product for over 10 years with very clean tanks as a result.

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #19 – May 16, 2018, 10:15:11 pm

We found our Gray tank smelled worse than Black tank. When we backflushed gray into black it made our black tank smell worse.

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #20 – May 17, 2018, 09:35:36 am

Quote from: AC7880 – May 16, 2018, 12:38:04 pm

On my coach, a 40' tag U320, one AAV is hidden up behind the bath sink bowel. Pulling out top drawer next to it gives "some" access. The kitchen sink # 2 AAV I can see by pulling some of the kitchen drawers out and looking behind. In the clothes hamper immediately behind the "turbo turd" toilet is #3 AAV, possibly for the toilet, possibly for the shower instead..

Behind the washer are two. One for washer, one "maybe" for the shower drain (though shower is cross coach so I could wrong on this) . To change these two I'll remove everything from top cabinet to get to the washer water hoses and power plug, take doors of washer closet for working space, pull the washer out into "hallway". While the washer is out I will clean the drier vent thoroughly.

The 5th AAV (the extra one behind the washer), "could" vent one of the sewer tanks (grey most likely) instead of a specific item on the interior of coach. I'll try and figure out /verify all the above when I get parts and do the work. I'll follow up here when I do.

5 total AAVs on our coach.

Question: Is your toilet a direct drop into the sewage tank, or a electric pump model? That may determine if a extra AAV is present.

Take some pics of how to get behind the wall.. I will look again and see if some screws are hidden.. I spent 20 min on figuring out how to remove the lower trim on the closet slide so I an check the bladder connections.. never did get it figured out until I called someone that has done it.. the whole trim piece removes not just the bottom.. DUhhh!!

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #21 – May 18, 2018, 01:00:22 am

First update. Drove 42 miles into Tucson to Home Depot. Bought 3 improved AAVs, and 2 old style AAVs (wasn't positive on fit and function). Picture one shows the white Studor Redi-vent part number20362 @ $18.52 each, side by side with the black Oatey part number 39012 @ $6.15 each.

The Studor comes with a adapter I did not need nor use (to adapt to a 2" ABS pipe). The Studor is direct fit and only a tiny bit larger in diameter than the Oatey.

Picture two shows a new Oatey next to original. Original had a curling rubber flapper, letting odors past the seal.
I replaced the orignal Oatey in the hamper directly behind the toilet with a Studor using Teflon tape. The old Oatey was not easy to remove - resisted even using channel locks.

I can now verify 100%, the AAV in the hamper behind the toilet is for the shower. I pulled the unsecured floor out of the hamper and checked the pipes, then with AAV removed turned on the shower and watched the water flow.

Next will be pulling the washer and replacing the two AAVs behind it.

Studor Redi-vent part number20362 @ $18.52 each (direct fit, 1.5" like original)
Oatey part number 39012 @ $6.15 each

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #22 – May 18, 2018, 02:39:53 am

It's crazy to me how expensive those Studors are - we paid about the same - but they sure have worked great for us. Solved our issues immediately, and now I keep a backup spare underneath

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #23 – May 18, 2018, 08:29:52 pm

First of two updates. I verified the one rooftop sewer vent services both black and grey tanks as I had expected.

I was unable to track the actual pipes due to no direct visual observation method. I dumped both grey and black tanks, closed the valves, ran a water hose to roof and ran water directly into the roof top sewer vent pipe.

Both grey and black were filling. I observed both separately several times at the dump valves with clear end attachment on sewer hose. I am one hundred percent certain the one rooftop vent is for both grey and black tanks.

I also pulled the washing machine and changed both air admittance valves behind the washer. I am now one hundred percent certain both AAVs are for the washing machine only. There are effectively 2 P traps, one is the washer drain hose, and the other is a quite small actual P trap. Each has it's own AAV.

I will post pictures and descriptions of doing the job in my next post..

Re: Sewer Odor, roof sewer vent, air admitance valves inside...

Reply #24 – May 18, 2018, 10:23:23 pm

This comment may be late to the game, but we had some unpleasant odors in our 2003 last year. I read about changing the AAV valves but decided to try the Cyclone Sewer vent first. No odor issues since that was installed. I do wonder how that will work on days where there is no breeze. We have lived in the motorhome fulltime for two months now.

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