BLACK WATER SMELL

[ajjoez]

Can someone tell me or better yet send me a photo of the vent under the bathroom sink? We have a 2002 Montana #3295 RK 5th wheel. We've had some bad smells when we flush the toilet and tried everything we know and that has been suggested, but nothing has really helped. Someone mentioned a vent under the sink, but we sure can't find it. We have to empty the black water tank every couple of days to keep the smell down when the AC in the bedroom is on (it really comes in then) and being in Texas both AC's are on most of the time. Any and all help will be appreciated.

[GreatWhite]

The two shouldn't be connected in any way to my knowledge. Do you, by any chance, have your Fantastic fan going when you flush? It'll suck the black tank odor into the room if all/most windows are closed.

[DQDick]

Your bathroom sink drain should be plumbed to your grey tank not your black so that shouldn't be your problem. It could be that your vent to your black tank is plugged or, if your rig is prepped for a washer/dryer and you don't have one, the problem could be coming from the open drain line for the washer.

[ajjoez]

Now there's a good suggestion. We do have the hookups for a washer and dryer, but we don't have them. We use the space for a closet. Where would we find the drain for the washer to see if it's open?

quote:Originally posted by DQDick

Your bathroom sink drain should be plumbed to your grey tank not your black so that shouldn't be your problem. It could be that your vent to your black tank is plugged or, if your rig is prepped for a washer/dryer and you don't have one, the problem could be coming from the open drain line for the washer.

[Irlpguy]

You are talking about an older Montana here, have you added a front AC recently and now have the problem or is there nothing new, but the smell has suddenly appeared.
The Gray water tanks are not connected to the Black water tank, although there is a possibility they may share a common vent. If you have a vent near your front AC then my guess would be it would be the bathroom vent and would be venting the black water tank. You could be getting air sucked in from the AC from that vent.

If the AC re-circulates air within the unit, then when you open the toilet valve to flush it may be drawing air down the vent and up from the toilet. This can happen with an exhaust fan as well because it has to have an air supply to exhaust, with the toilet valve open it will draw air down the vent pipe and could also cause a smell to come from the black tank.

The sinks should all have traps on them and should allow no odors to come back from their holding tanks.

The drain for your W/D should be capped if not in use, and would not be going to the black water tank in any case.

[Drifty1]

I have the same rig and have noticed a black water smell at times. I am thinking that it is a pluged vent on the black water tank. I also need to look at the plumbing for the w/d as I do not remember if there is a p trap on that drain. I have noticed it is a lot stronger after using the tank flushing line which leads me to the vent or plug in the w/d connection.

[ajjoez]

If you figure it out, i'd appreciate it if you'll let me know what it is and how to fix it. Thanks, ajjoez

quote:Originally posted by Drifty1

I have the same rig and have noticed a black water smell at times. I am thinking that it is a pluged vent on the black water tank. I also need to look at the plumbing for the w/d as I do not remember if there is a p trap on that drain. I have noticed it is a lot stronger after using the tank flushing line which leads me to the vent or plug in the w/d connection.

[DQDick]

First the drain pipe should be near the water outlets. Second many have run that drain line and found all kind of things growing there. Third over the years Keystone has run that drain all over the place. On ours that drain goes into the gray tank on others it went out all on it's own and on a few it did go into the black tank.

[The Oldguard]

quote:Originally posted by Irlpguy


The drain for your W/D should be capped if not in use, and would not be going to the black water tank in any case.

Wrong!!! The 2005 (3400RL) went into the black tank, and there were other units

[JandC]

We recently had our W/D installed and I asked the tech if we needed to leave one of the grey valves open when doing loads. He said our unit had its own independent drain that did not go into any of the three tanks. I would check your roof mounted caps on the tank vents to make sure they are venting ok. I recently replaced one of mine with the new type that just pushes on. We started getting sewer smell in the kitchen area and I discovered I had pushed the vent cap down too far and it was not allowing the vent pipe to vent properly. I pulled the cap up about 3/4 of an inch and no more sewer smell.

[ajjoez]

Will sure check that out; makes more sense than anything so far. We have washer hookups, but have never had a washer so I doubt the smell could have anything to do with that. Thanks, ajjoez

quote:Originally posted by JandC

We recently had our W/D installed and I asked the tech if we needed to leave one of the grey valves open when doing loads. He said our unit had its own independent drain that did not go into any of the three tanks. I would check your roof mounted caps on the tank vents to make sure they are venting ok. I recently replaced one of mine with the new type that just pushes on. We started getting sewer smell in the kitchen area and I discovered I had pushed the vent cap down too far and it was not allowing the vent pipe to vent properly. I pulled the cap up about 3/4 of an inch and no more sewer smell.

[ileyld]

quote:Originally posted by ajjoez

Can someone tell me or better yet send me a photo of the vent under the bathroom sink? We have a 2002 Montana #3295 RK 5th wheel. We've had some bad smells when we flush the toilet and tried everything we know and that has been suggested, but nothing has really helped. Someone mentioned a vent under the sink, but we sure can't find it. We have to empty the black water tank every couple of days to keep the smell down when the AC in the bedroom is on (it really comes in then) and being in Texas both AC's are on most of the time. Any and all help will be appreciated.

[Irlpguy]

Old Guard wrote:

quote:
Wrong!!! The 2005 (3400RL) went into the black tank, and there were other units

I forget we are dealing with a product where there seems to be no standard plumbing or wiring, in 2005 all or some could have had the plumbing for the W/D go to the black tank, however if it did and the drain from the W/D was capped then "no" smell should come from there.

The black tank "should" have a roof vent, the AC can draw smell in from that or as I stated when the toilet is flushed and the AC or something else is trying to draw air from the outside with no window open then it can come in from the vent and out the toilet.

As suggested, check your roof vent, especially if it is near the front AC. Check to make sure the W/D drain is capped as well.

[WaltBennett]

One more thing - if your bathroom vent is open, you may be getting odor from the black tank vent wafted down into your air vent. I've had that happen on a class C I had years ago. Put one of those swiveling vent tops on and that pretty much eliminated the problem.

[ajjoez]

Our grey water goes into the black water tank. When I drain the black water, I close the handle and open the grey water and it helps clean out the black water hose. ajjoez

quote:Originally posted by DQDick

Your bathroom sink drain should be plumbed to your grey tank not your black so that shouldn't be your problem. It could be that your vent to your black tank is plugged or, if your rig is prepped for a washer/dryer and you don't have one, the problem could be coming from the open drain line for the washer.

[ajjoez]

Yep our grey water from the bathroom goes into the black water tank. ajjoez

quote:Originally posted by The Oldguard

Wrong!!! The 2005 (3400RL) went into the black tank, and there were other units

[DQDick]

[quote]Originally posted by ajjoez

Our grey water goes into the black water tank. When I drain the black water, I close the handle and open the grey water and it helps clean out the black water hose. ajjoez

What your are describing here is what most of us do. When you shut the black water valve it's shut, but stuff is still in the drain pipe after the valve. When you open the grey tank it then floods the sewer pipe and cleans that out. It doesn't go thru the black tank it goes thru the shared sewer pipe.

[sreigle]

quote:Originally posted by The Oldguard

Wrong!!! The 2005 (3400RL) went into the black tank, and there were other units

Old Guard is correct. Early models were plumbed into the shower gray tank. I know because twice with our 2003 3295RK I forgot to open the shower tank valve and the washer flooded up and over the shower tub into the rig. Twice.

Then they plumbed into the black tank for a year or so. I guess they thought that would help keep the tank cleaner. But that really opened up a scary scenario of forgetting to open the valve to the black tank and overflowing the toilet or out the roof vent.

Then they plumbed directly to the main dump line, not into any tank. Our 2007 3400RL is this way. It was built 8/18/06.

Bottom line is if his year has washer plumbed to the black tank then I would think it possible to get black tank smells from an open washer drain pipe. Maybe it has a check valve but I've never seen a check valve large enough to handle the flow from a draining washer. Or if there is one it could be bad.

We also sometimes get the black tank smell inside, usually when dumping. We have no drips underneath so don't think we have a leak. I suspect it's the pressure differential between outside and inside that's allowing vent fumes to get sucked into the rig. I have read many times that those free-rotating vent caps you can put on the black tank vent can prevent this problem. But I have no idea whether they really work and work consistently.

[sreigle]

quote:Originally posted by ajjoez

Can someone tell me or better yet send me a photo of the vent under the bathroom sink? We have a 2002 Montana #3295 RK 5th wheel. We've had some bad smells when we flush the toilet and tried everything we know and that has been suggested, but nothing has really helped. Someone mentioned a vent under the sink, but we sure can't find it. We have to empty the black water tank every couple of days to keep the smell down when the AC in the bedroom is on (it really comes in then) and being in Texas both AC's are on most of the time. Any and all help will be appreciated.

This rig has that "vent" in a different location and not one that's easily accessible, so I can't get you a photo. However, our 2003 Montana had that vent under the vanity. It's a checkvalve for the black tank flush. There were two lines coming up out of the floor and the valve connected the two lines at the top. It's shape looks like an inveted "U" or a staple with very, very long legs. The valve should just screw into place (I think).