Black tank odor

kketterling · 07-31-2011, 10:24 AM

I'm getting black tank odor from under my bathroom sink. I remember discussion on this site regarding a check valve or something that's under the Sink that can malfunction. Can someone help me out and let me know what I need to do to make the smell go away? Do I need to clean or replace the check valve?

**RickO** · 07-31-2011, 10:30 AM

I don't have a Monaco but I think the check valve you're referring to is usually mounted on top of a vertical pipe usually under the sink and can be found at Home Depot, etc. I suspect it's grey tank rather than black tank you're smelling. It can be just about as bad.

Good luck

Rick

njs42 · 07-31-2011, 11:34 AM

Most likely the grey tank as said before. I don't think these check valves fail often---I used to suspect mine as well----even had it replaced--odor rteturned???

Black tanks vent through the roof.

Odors travel---if you have your ceiling vents up and a Fantastic/or fan pushing air out at another point it can draw odors in from the roof vent---just a suggestion. We had that experience until I added an extension and a device that draws away odors from the roof vents.
Do you have a washer/dryer---if so are you sure the pee trap has water in it---they dry out in the summer and if you do not use it then it can cause odor. Just run the thing and the odor will stop if that is the cause.

Just some thoughts-------------------hope it helps.

ArmyEOD · 07-31-2011, 11:39 AM

May also pour some water in your washer drain line pipe. Some times the trap will dry out and it can stink.

If it is the sink drain line vent, you take it off you can clean the rubber disk with soap and water and then spray it with 303, armorall, sun of a gun or what ever you have. But if you need to by one just check the box stores. They will have them. +/- 5.00. The whole thing just screws off.

Acker1 · 07-31-2011, 09:01 PM

I just got done fixing a stink under my bath sink. Since I can't smell (DW can!) it was even harder. I replaced the vent and still stunk. Finally took the bottom out of the cabinet and filled all the holes for the plumbing & wiring with spray foam. Smell is now gone.

DICK

kketterling · 08-02-2011, 02:52 PM

Ok had a chance to look under the sink in the stool area and I'm pretty sure this one vents back from the black tank as I was told this sink drains into the black tank. I actually have three of these vents one under the kitchen sink, another under the sink by the shower and the one by the stool. I tried to turn the vent out by hand and also with a small pair of channel locks without any luck. So before I break something I decide to cover the vent with a plastic bag and a rubber band. If smell continues will look elsewhere. It maybe I just need to empty the tanks since its been about 2 weeks since I've dumped and they are about 2/3 full.

njs42 · 08-02-2011, 04:43 PM

Dump and flush by putting another 2/3rd water in and dump again. Make sure you do not cover the vent while you dump it will impede flow I think.

RVNeophytes2 · 08-02-2011, 05:58 PM

Quote:

Originally Posted by ArmyEOD

May also pour some water in your washer drain line pipe. Some times the trap will dry out and it can stink.

If it is the sink drain line vent, you take it off you can clean the rubber disk with soap and water and then spray it with 303, armorall, sun of a gun or what ever you have. But if you need to by one just check the box stores. They will have them. +/- 5.00. The whole thing just screws off.

For good measure, I put the thing to my lips and sucked...

Learn from my stupidity, and DON'T do this at home.

kketterling · 08-11-2011, 01:58 PM

Drove the coach to Cisco Grove with black tank about 2/3s full and no black tank odor. Removed the plastic bag I put over the ventunder the sink turned on exhaust

kketterling · 08-11-2011, 02:08 PM

Quote:

Originally Posted by kketterling

Drove the coach to Cisco Grove with black tank about 2/3s full and no black tank odor. Removed the plastic bag I put over the ventunder the sink turned on exhaust

Sorry hit sent before I finished.

Turned on exhaust fan and odor started coming out of vent. So it looks like I either need to replace the vent under the sink or leave the plastic bag on it. Usually replacing the vent would be simple but this one is on really tight. Any tricks on how to get this one loose? I'm afraid if I put much pressure on it I'll break the pipe it's attached to so I may have to cut it. Leaving the bag on would be the easiest fix.

pcarrell · 08-11-2011, 03:22 PM

It just has plastic threads you should be able to remove turning counterclockwise.

kketterling · 08-11-2011, 03:43 PM

I agree but I think someone at the factory thought it needed to be turned on really tight and there's not alot of room to work with it under the sink.

JohnCamelot · 08-12-2011, 08:47 AM

Here's a simple thought. I have the same problem if I run the Fantastic fan with all the windows closed. It will then suck air out of your grey tank vents, and you get the smell. If you crack a window open you may not have a smell issue. At least, that's what worked for me.

Just a thought, based on my experience...

== John