Sewer smell

spkrvr · 12-27-2014, 12:27 PM

We have a 2014 Rockwood 2604WS. We get a sewer smell when we turn on the ceiling fan in the bathroom or turn on the air conditioning. Seems to be strongest arouNd the sink area. Have checked all pipes and stink pipes on the roof. Have sealed these pipes where they come through the roof. Any ideas on how we can stop this?

**dcheatwood** · 12-27-2014, 12:31 PM

Has the TT been setting up for a while? If so, the pea trap, vapor seal may be dry from evaporation. That allows vapors to come up thru sink and shower drains. If so run some water in each drain to fill it again and see if odor is still there.
Check roof vent for blockage. Could be blocked with dirt dobbers or spider webs and preventing adequate venting.
Just a couple ideas

**Platokidd** · 12-27-2014, 01:06 PM

First off welcome to the best rv forum! This site is great place to find and share info. We have a lot helpful folks on here.

Now to add to what dcheatwood said, do you use any oder control??

Amazon.com: Camco 40256 TST Gray Water Odor Control - 64 oz: Automotive

Amazon.com: Camco 41172 Orange TST Holding Tank Chemical - 64 fl. oz.: Automotive

Always keep a few gallons of fresh water in the holding tanks helps too. Never leave them empty.

Helmsey · 12-27-2014, 03:13 PM

Another option is the air admittance valve on the sink pipes. We have had issues with 2 of ours and after unscrewing the existing ones, and screwing on new ones the smell seemed to go away.

irish01 · 01-08-2015, 06:22 PM

Hey guys,
Similar problem. We are boondocking in daughter's yard while I get over major surgery. Black tank got very full before we could go dump it and sewer odors got heavy inside. After we dumped yesterday and ran half an hours worth of water through the "flush black tank" feature of the rv (cedar creek 36rd5s), the smell is still present today. Could the contents of the black tank have overflowed into any other parts of the rv instead of backing up to the bathroom?
Thanks for any help,
Tom

Ford Idaho · 01-08-2015, 06:59 PM

Does your unit have a Dometic 300 toilet?

https://www.google.com/webhp?tab=ww&...+toilet+recall

**dcheatwood** · 01-08-2015, 08:34 PM

Look into the first open area of your toilet, just under the flush seal. Sometimes waste can get in there and will smell. I've cleaned it out before with a pump spray bottle with bathroom cleaner. Sprsy anything you can see. Or if your shower head will reach, hose the toilet insides down with hot water. Just a thought.

rattleNsmoke · 01-08-2015, 09:41 PM

There's a black plastic vent check valve, probably under your sink, that has a rubber diaphragm that gets stiff and allows fumes into the coach. It's an easy replacement since it screws off. I've used a lil' cooking oil on the diaphragm and that seemed to soften it and work. Good luck....

irish01 · 01-09-2015, 09:55 AM

Thanks for the replies. It is so heavy an odor it fills every room in the coach. We yried running the kitchen vent fan and opening a few windows but that seemed to make it worse. Probably the least affected area is the bathroom and the toilet seems to not be the source. But I'll follow all suggestions till I find it or the wife leaves, lol.

Thanks,

Tom

Helmsey · 01-10-2015, 10:32 PM

Quote:

Originally Posted by rattleNsmoke

There's a black plastic vent check valve, probably under your sink, that has a rubber diaphragm that gets stiff and allows fumes into the coach. It's an easy replacement since it screws off. I've used a lil' cooking oil on the diaphragm and that seemed to soften it and work. Good luck....

AKA....air admittance valve

cbconway · 01-11-2015, 10:03 AM

Quote:

Originally Posted by Ford Idaho

Does your unit have a Dometic 300 toilet?

https://www.google.com/webhp?tab=ww&...+toilet+recall

X2 This drove us crazy for a few months. Dometic was very good about replacing.

Ford Idaho · 01-11-2015, 10:09 AM

Quote:

Originally Posted by cbconway

X2 This drove us crazy for a few months. Dometic was very good about replacing.

Did you really get an old 300 in your 2015?

I would have thought those were all used or replaced by 2014.

cbconway · 01-12-2015, 08:49 AM

Quote:

Originally Posted by Ford Idaho

Did you really get an old 300 in your 2015?

I would have thought those were all used or replaced by 2014.

My signature has changed. We had a 2013 Flagstaff 21FBRS with the 300. We wanted more room & traded up in December. (Too bad signatures are retroactive -- it looks silly sometimes).

oxcamper · 01-12-2015, 09:19 AM

Make sure your black tank hasn't shifted and the pipe joint at the tank has come loose. Happened to ours and after trying everything to no avail, I peeked under the underbelly panel and sure enough that's what happened. dealer resecured the tank and the problem went away.

jz5w63 · 02-12-2015, 12:19 PM

We had a black water leak from our new 2014 Forest River Flagstaff 5th wheel which the dealer "fixed". It was like living over a sewer before the fix as there was sewage dripping out the vent in the plastic underbelly of the trailer. The repair seemed to work for a couple of one week, short drive camping trips but after pulling to Florida (1200 miles) this January it was leaking again so we paid a mobile RV place to fix it again. What they found was a loose hose clamp around the tank discharge fitting to valve push-in fitting. Also upon removing the valve push-in fitting it appeared that there were tank plastic injection mould separtion grooves on either side of the tank fitting that the o-ring could not seal against and the soft grey goo sealant wasn't sealing. He cleaned this grey sealant out and reinserted in combination with a lot of polyurethane grey colored sealant which cured hard in addition to replacing the large hose clamp and tightening it super secure. I then later wrapped it over with silicone self vulcanizing tape (through an access hole that was cut and covered with a replaceable access hatch by the dealer in the original "fix") as an added safeguard. Twice testing by filling the tank and checking for leakage proved this had fully repaired the leak. HOWEVER we did later and still get smells when the tank is filled after several days of use. In all cases the smell is worse in the kitchen area where the furnace air intake grill is as the area behind it is open to the underbelly for piping and ductwork runs. We have found that the smell is the worst when running the bathroom exhaust fan especially when the windows in the trailer are closed. It seems that the exhaust fan is pulling in air from leakage points (negative pressure created by fan) and with the windows closed it is pulling the air from the bottom of the trailer which is closely sealed but not a perfect seal. Opening the windows (though not wanted in colder temperatures) seems to reduce the issue. The question still remains as to where the odor is coming from as the leak is now fixed! Even before flushing or after flushing (making sure to leave a a water seal above the slide valve in the toilet) the smell is strong and we have found that when taking a shower with the fan on we still get smells, toilet in use or not! I'm guessing that the problem is the roof vent and will take the cap off to see if the vent pipe is sealed or open around its anular area. If open then I'm guessing that the normal tank venting due to vapour creation and heating in the tank (smell is much worse in 80+ temperatures) is drawn by the fan negative pressure back through the unsealed anular perimeter of the vent pipe down the wall of the tank, into the underbelly and then into the trailer interior. I know people have tried the revolving siphon vents that they put on in place of the cap and these probably solve a similar problem by ensuring that the tank vented odors indeed get pulled out and don't get pulled back into the trailer. But, I suspect this is putting a bandage on the problem while just making money for the people that sell the vents, again, and again (when they apparently fall, blow, or get knocked off). We had a 2005 Rockwood 5th wheel that I had taken the caps off of to insert a hose down the vent pipes to clear (because black water would not drain). This did clear the vent pipe and the black water was then able to drain normally. However, at the time I did notice that indeed at the roof area inside of the flashing the vent pipe was loose and I did seal it with foam before replacing the cap. I expect to find the same issue and will report back later. BTW an experienced RV'er told us they simply fold over the TP and put it in a plastic bag in a waste basket beside the toilet and then dispose of it in the garbage. This ensures that the TP doesn't block the vent or drain valve or cling to the level sensors. They obviously believe in the old advice for boat heads - "Don't put anything in the head that hasn't gone into your mouth!" Also, we were told as others have said, to always let the black water fill to 2/3 or more and then drain to allow hydraulic pressure and flow to remove the solids. We also pressure flush before we pull out and leave a little clean water in the tank to slosh around. Not sure about tank treatments - still using the blue Camco stuff for now!

jz5w63 · 02-12-2015, 03:49 PM

Did the check of my roof top vents from my tanks and as suspected, and the same as on our previous FR Rockwood 5th wheel, the ones on our 2014 FR Flagstaff are done the same way. The factory cuts an oversize hole in the roof and extends the vent ABS pipe up through the holes and lets them bang around loose at the top. The result is that these unsealed openings allow sewer/tank gas/vapors from the vents to be sucked back in if you run the bathroom (or other) roof top exhaust fan(s) if you have the windows and door closed and to a lesser extent if the windows/doors are open. The result is that by creating a negative pressure (exhausting cabin air that must be replaced by air from outside) then the smells are just short circuited right back into the trailer via the opening around these roof vents. Putting the previously discussed after market whirrlybird vent tops on just cuts into your spending pocket book and puts a bandaid on the problem. I did succeed in using some airconditioner 1 inch x 1 inch square foam rubber sealer to push in around the vent pipe and block this anular opening around the vent pipes and then finished it off with some silicone sealant. The result is that this short circuit airflow cannot now occur and the foam/sealant still allows some flexing for expansion/contraction of the vent pipe. No further smells have been detected at this time although Florida February temps are in the daytime 60's and low 70's right now instead of 80's/90's when the smell is the worst. I will update as time progresses re the effectiveness of this fix. Note in the pictures that the vents are in direct line with the discharge from the bathroom vent which isn't helped by the weather cowl on the vent which directs the smell/air toward the vents thereby helping the short circuit airflow. Hopefully, this seal/sealant will stop the problem once and for all!

ts12i30 · 05-23-2015, 08:56 AM

Hey ha, I've got a similar issue. Did your fix solve the odor problem?

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jz5w63 · 05-23-2015, 09:49 AM

Yes the work I did on the roof vents has solved the sewer smell problems we would get when we ran the bathroom or other exhaust fan with the windows closed. Now the fumes normally venting from the vents goes out instead of being sucked back down around the vent pipe and into the camper. That combined witht the initial and main sewer smell issue which was a leak at the blackwater tank drain out fitting have solved our problems. If you don't have any blackwater drain piping issues and you get smells when you run an exhaust fan then this is likely your solution. As others have done you could add the whirly bird caps to the top of your vents but then I have heard they eventually fall off. Moreover, they just use a wind powered siphoning effect to make sure that the vent odors do get out, but when there is no wind, well, then you'll still have the smells. I think my solution is a better complete fix for the vent problems.

ts12i30 · 05-23-2015, 11:24 AM

Thanks jz. I'm going up to the roof with my call gun and some foam like you used. I'm hoping this will be the fix. I've already replaced the air admittance valve under the sink.

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ts12i30 · 05-23-2015, 05:45 PM

You're a lifesaver jz. I took the vent caps off and used some foam to fill the gap between the pipe and the housing. Then topped it off with silicone caulk. After a few hours, I closed all the windows and ran the fan. No odor at all. Thank you very much for posting your repair. Take care.

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