black tank vent pipe slipped down?

Motorhome05 · 08-25-2007, 02:07 PM

We have been living in our mh for 2 years and have not had a problem with black tank odors until May of this year. We have not changed brands of chemicals. All of a sudden, we have to dump the black tank every 3 days because of the odor. This happens even if we use the campground facilities for more odorous stuff (guess that is a polite way of saying that.) We have changed the vent caps to those that move with the wind, have filled the tank and put in chemicals and traveled down the road to clean the tank, we have used a wand when dumping to make sure we have removed all the "stuff". I did read on one forum where the black tank vent pipe might slip down into the tank so, am wondering if anyone knows of this happening and how to fix it. Any suggestions, greatly appreciated.

Thanks,

Motorhome05 · 08-25-2007, 02:07 PM

We have been living in our mh for 2 years and have not had a problem with black tank odors until May of this year. We have not changed brands of chemicals. All of a sudden, we have to dump the black tank every 3 days because of the odor. This happens even if we use the campground facilities for more odorous stuff (guess that is a polite way of saying that.) We have changed the vent caps to those that move with the wind, have filled the tank and put in chemicals and traveled down the road to clean the tank, we have used a wand when dumping to make sure we have removed all the "stuff". I did read on one forum where the black tank vent pipe might slip down into the tank so, am wondering if anyone knows of this happening and how to fix it. Any suggestions, greatly appreciated.

Thanks,

Randyat1001 · 08-25-2007, 02:34 PM

Is your toilet holding water in the bowl? I have seen that as a problem when you flush and then fill the bowl and the water leaks throug. You need that water seal because the toilet does not have a trap. Someone on this board turned me on to the fact that when you flush you need to allow the valve to close hard so you push the pedal or lever and release it so it closes with a snap rather than doing it slowly.

Motorhome05 · 08-25-2007, 05:05 PM

Yep, toilet does hold water.

Randyat1001 · 08-26-2007, 03:08 AM

Next step might be to pour some water into the vent to make sure it is clear and if it is then use something that has a scent and spray into the vent on top to help locate a leak in the vent.

Pubtym · 08-26-2007, 03:15 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Randyat1001:
Is your toilet holding water in the bowl? I have seen that as a problem when you flush and then fill the bowl and the water leaks throug. You need that water seal because the toilet does not have a trap. Someone on this board turned me on to the fact that when you flush you need to allow the valve to close hard so you push the pedal or lever and release it so it closes with a snap rather than doing it slowly. </div></BLOCKQUOTE>

As per toilet instructions, for a sticking valve...does not close completely....use some silicon spray in spray can bought at Walmart.

Turn off all water to coach. Drain remaining water in toilet flush system into tank. Spray all valve surfaces/edges...seal surfaces...and work flush valve several times allowing to "snap" completely closed. Partially open valve again...spray all mentioned surfaces again and repeat closure cycles (snap). Turn on water again and flush several times.

I keep a can of the spray silicon in the bathroom closet for regular/weekly valve lube-maintenance.

Also, consider installing a CAMCO sewer vent cover as per other posts in this forum.

dawg · 08-26-2007, 03:41 AM

If your unit only has one vent stack through the roof, then I would suggest checking the vacuum breakers under each sink. The smell from gray water is horrible.
My 99 Adventurer only has one vent stack, and the two tanks are vented that way. The vent stack is actually in the gray tank with the black tank teed into that. The vacuum breakers a about $5.00 at your local home supply store. They are suppose to allow for dumping, without empting the "P" traps.
The other problem I had was the rubber gasket where the pipe from the toilet connects to the tank had split.
Just something else to check. hope this helps.

Clay L · 08-26-2007, 05:04 AM

The tanks I saw being built at the Winnebago factory were roto-molded with a flange molded into the top of the tank. The vent tube is coupled to that flange and can't slip down into the tank. I think they have been made that way for many years.
Like the other poster (dawg) said I would suspect the vacuum breakers under the sinks.

Motorhome05 · 08-26-2007, 05:25 AM

What does a vacuum breaker look like? We have a Vectra 36gd. Are the vacuum breakers hard to change? Any suggestions as to what exactly I am looking for? -color-size-shape- Thanks. Please excuse my lack of knowledge as to plumbing.

Clay L · 08-26-2007, 01:18 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Motorhome05:
What does a vacuum breaker look like? We have a Vectra 36gd. Are the vacuum breakers hard to change? Any suggestions as to what exactly I am looking for? -color-size-shape- Thanks. Please excuse my lack of knowledge as to plumbing. </div></BLOCKQUOTE>
Below is a picture of the one under my bathroom lavatory. It's the black cylinder on top of the stub coming off the drain line trap. It's on the top right side of the picture in the corner. There is a white water supply line running diagonally across it.
I haven't removed one yet but I understand it just unscrews. They should be available at most hardware stores.

dawg · 08-26-2007, 02:47 PM

The vacuum breaker just screws off. When I replaced mine I used teflon tape on the threads also.

Motorhome05 · 08-26-2007, 02:59 PM

Clay-thanks for the picture. We will be taking the vacuum breaker off and heading for the hardware store tomorrow. Thanks to all who have made suggestions for solving our stinky problem.

Slapshottr · 08-26-2007, 03:43 PM

I have another black water question. I have black water leaking into the sewer compartment area. Only happens when tank is half to 3/4 full and driving on rough roads. Happened last two times after dry camping on the way home. Looks like it is comming off the top of the tank towards the front. I figure it has to be the toilet seal or the seal on the vent pipe. No way to see top of the tank on the 38T with out some major work. Does not happen while camping or on the road with only a few gallons in it. I used the built in flush to fill the tank to 3/4 and let it sit no leaks. I guess I'll have to take it all the way up to the toilet to check the seal. Anyone have any other ideas? The other thing it could be is a crack in the tank. Anyone ever have this happen? Thanks.

dawg · 08-26-2007, 04:23 PM

After removing the toilet, you will also have to remove the toilet flange which is screwed to the floor. There is a rubber seal/gasket that slips into the top of the tank. This seal/gasket (I don't know the real name)seals the tank and pipe from the toilet. I think it's 3 inches and should be available at you RV dealer. It just slips into the hole in the top of the tank and the pipe from the toilet slides through. We had one split, and we also had a leak & odor.

"007" · 08-26-2007, 06:27 PM

You can shine a flashlite down the toilet pipe and take a look. If you see a half moon of toilet paper your pipe was not glued into the floor flange and has dropped down into tank causing spillage on top of your black tank, makes for a mess.

You will have to remove toilet and pull pipe up enough to fit in flange and use pipe cement to hold. Than spray some bleach water mixture to elimiate the oders and air out compartment.

Motorhome05 · 08-27-2007, 04:27 PM

We only found one vacuum breaker. It was under the kitchen sink. We have 2 vent pipes on our 05 Vectra GD. We replaced the vacuum breaker and now only time will tell. We could not find a vacuum breaker under the bathroom sink.

Motorhome05 · 08-31-2007, 03:42 PM

Update----We switched the vacuum breaker under the kitchen sink (we only have one) and all is well. We have not had odor from the black tank for the last five days-before we could only go 3 days before we had odor and that was with us using the campground facilities.