Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Display Modes
Old 08-10-2018, 05:54 PM   #1
Junior Member
 
Join Date: Jun 2018
Posts: 6
When ac is running the rv smells like black tank

We have a 2018 cck with 2 acs and have noticed when the acs are running there is a smell of the black holding tank throughout. Any ideas why? is the ac sucking in air from the tank vent?
carlknowles is offline   Reply With Quote
Old 08-11-2018, 04:45 AM   #2
Site Team
 
Join Date: Mar 2008
Location: Southwest Alabama
Posts: 9,850
You most likely have an air admittance valve leaking by. They're located under sink and lavatory cabinets near the top.
__________________
Salem 29RKSS Pushing a GMC Sierra 2500HD!
Gotta go campin!
Bama Rambler is offline   Reply With Quote
Old 08-11-2018, 10:48 AM   #3
Denver To Yuma In 90 Days
 
Join Date: Mar 2018
Location: Yuma, Arizona
Posts: 3,882
It is also possible that your roof vent for the black tank is located near an AC unit, which may be pulling the fumes from the vent back into the RV through the AC.

There are alternatives to the stock roof vents available.
JohnD10 is offline   Reply With Quote
Old 08-11-2018, 10:55 AM   #4
Senior Member
 
bubbles's Avatar
 
Join Date: Dec 2012
Posts: 7,645
The AC doesn't pull air from outside it recirculates the air inside and is supposed to be sealed from all outside inputs. Just like at home.
bubbles is offline   Reply With Quote
Old 08-11-2018, 12:20 PM   #5
Member
 
Join Date: Feb 2014
Posts: 46
if your smelling something in your unit with the A/C running, then the odor is coming from inside the unit.
chapelt is offline   Reply With Quote
Old 08-11-2018, 12:39 PM   #6
Senior Member
 
Join Date: Jan 2018
Location: Raleigh, NC
Posts: 9,458
Are you sure?

Quote:
Originally Posted by JohnD10 View Post
It is also possible that your roof vent for the black tank is located near an AC unit, which may be pulling the fumes from the vent back into the RV through the AC.

There are alternatives to the stock roof vents available.
The RV air conditioners I've looked at don't seem to be designed to pull in any fresh air; should just recirculate. If they drew in fresh, hot air, it would take even longer to cool the RV down.

There's always the possibility of a little leakage of course. For example, a bit of air could leak through the drain port on the evaporator (which is in the path of inside, circulated air).

My vote is for the the under-sink air admittance (vacuum breaker) valves.

Larry
Larry-NC is offline   Reply With Quote
Old 08-11-2018, 12:44 PM   #7
Denver To Yuma In 90 Days
 
Join Date: Mar 2018
Location: Yuma, Arizona
Posts: 3,882
Quote:
Originally Posted by JohnD10 View Post
It is also possible that your roof vent for the black tank is located near an AC unit, which may be pulling the fumes from the vent back into the RV through the AC.

There are alternatives to the stock roof vents available.
I have heard of this happening more than once...

So it is a distinct possibility.
JohnD10 is offline   Reply With Quote
Old 08-11-2018, 01:41 PM   #8
Junior Member
 
Join Date: Jan 2015
Posts: 17
I have a 2015 FR Cardinal. I have been experiencing the same thing. I replaced both my under counter vents and still have this problem from time to time. I have tried all sorts of chemicals for the tanks. I am going to change out the stock roof vents with the 360 vents.

I live in Phoenix and the temps have been really hot. Im thinking that the chemicals arent rated for this freakin heat.
lesterw is offline   Reply With Quote
Old 08-11-2018, 01:55 PM   #9
Senior Member
 
Iwannacamp's Avatar
 
Join Date: Aug 2013
Posts: 7,916
Might try to put a stopper in the bath tub/shower and sinks in the bath and kitchen. If it goes away you know where to look.
This is also assuming the air admittance valves are functional
__________________
2017 Puma 297RLSS
2005 Ram 2500 4X4 diesel SMOKER!!
I love puns, irony and tasteless jokes...
born in Texas.... live in Arkansas
Iwannacamp is offline   Reply With Quote
Old 08-11-2018, 01:56 PM   #10
Senior Member
 
Splitshaft's Avatar
 
Join Date: Jul 2018
Posts: 273
Add some perfumed liquid to the black tank and run the AC’s to verify the odor is black tank odor and not mold odors coming from the AC’s themselves. Mold can smell just like poo. If the source of the odor is from the black tank and it can be the gray tank too as they can get quite stinky! The AC’s units are leaking indoor air to the outside of the coach and holding tank air is coming into replace the air the AC’s pump out through leaks in the AC’s or leaks in the roof ducts. It is best to find and fix the external leak of the AC. Under counter plumbing vents can be a source of odors as well as the commode as it is open to the holding tank. Unless the roof plumbing vent is plugged, there is not a roof plumbing vent made to stop negative pressure in the coach from pulling in makeup air. If the AC units themselves are molding inside, they will need to be cleaned to destroy mold growth. One problem with AC’s that shut off once the thermostat is satisfied, is the evaporator coil stays damp and becomes a source for mold and mildew to grow and thrive. It is best for the AC fan to stay running and dry the moisture from the evaporator coil to prevent mold growth and odors.
Splitshaft is offline   Reply With Quote
Old 08-11-2018, 03:04 PM   #11
Senior Member
 
Join Date: May 2015
Posts: 230
Pull down the ceiling panel to the a/c. Check up in the opening and look for any openings in the tape around the duct from roof to ceiling . You can pull air from the “attic “ area and if the tank vent tube does not project fully through the vent base enough to seal odors can drop into the roof space and be pulled into the return air space.
hillsdaletc is offline   Reply With Quote
Old 08-11-2018, 03:20 PM   #12
Senior Member
 
Mountainmanbob's Avatar
 
Join Date: Oct 2011
Location: Lakeside mountains, Calif
Posts: 755
Look for mold.
M-Bob
Mountainmanbob is offline   Reply With Quote
Old 08-11-2018, 04:07 PM   #13
Junior Member
 
Join Date: Aug 2018
Location: Rapid City, SD
Posts: 2
I had the same unpleasant experience happen to me one time. At a state park in Indiana last year. It was a warm humid day and I was running my air conditioner. The smell was a sulfur smell not unlike the smell eggs can make. But much stronger. My first suspect was the air conditioner because it seemed to be coming from there. Long story short, it was the water I filled up with at the state park. My theory is that the high sulfur content of the park's water reacted with the anode in the hot water tank. As stated before, the AC fan was pulling this foul air from somewhere. I confirmed the probability of the water having a high sulfur content with my brother-in-law who has drilled wells in the area. I later docked at his house and replaced the water in my tank with soft water. No problems after that. It has not happened since. I do have an onboard carbon filter, but this did not seem to help with the suspect water.
GeoAuDog is offline   Reply With Quote
Old 08-11-2018, 04:52 PM   #14
Senior Member
 
Join Date: Jan 2018
Location: Raleigh, NC
Posts: 9,458
If you've never encountered this...

Quote:
Originally Posted by GeoAuDog View Post
I had the same unpleasant experience happen to me one time. At a state park in Indiana last year. It was a warm humid day and I was running my air conditioner. The smell was a sulfur smell not unlike the smell eggs can make. But much stronger. My first suspect was the air conditioner because it seemed to be coming from there. Long story short, it was the water I filled up with at the state park. My theory is that the high sulfur content of the park's water reacted with the anode in the hot water tank. As stated before, the AC fan was pulling this foul air from somewhere. I confirmed the probability of the water having a high sulfur content with my brother-in-law who has drilled wells in the area. I later docked at his house and replaced the water in my tank with soft water. No problems after that. It has not happened since. I do have an onboard carbon filter, but this did not seem to help with the suspect water.
People who have never encountered high-sulfur water just won't believe it can have such a strong odor. We were stationed in southern New Mexico (Las Cruces) for two years in the early 70's. The town had five wells, three of which weren't bad and two of which had high sulfur content. We lived in a two-story townhouse. When I entered the house on the first floor and DW was taking a shower on the second floor, I could have sworn someone was scrambling eggs in the kitchen.

It's easy to see how you could smell this odor (and not recognize it as sulfur) if you were in a densely-packed campground and someone was watering a garden or washing a dog/kid/trailer or using a swimming pool nearby. Anything that atomized (misted) the water would do it.

Larry
Larry-NC is offline   Reply With Quote
Old 08-11-2018, 08:27 PM   #15
Senior Member
 
Villagerjjm's Avatar
 
Join Date: Aug 2017
Posts: 852
Check your air admittance valves first, then open up the air conditioner. If it runs air through vents, check those too!! Something may have crawled in there and croaked.
Villagerjjm is offline   Reply With Quote
Old 08-11-2018, 10:50 PM   #16
Senior Member
 
Join Date: Jan 2013
Location: Space Coast of Florida
Posts: 3,967
Quote:
Originally Posted by carlknowles View Post
We have a 2018 cck with 2 acs and have noticed when the acs are running there is a smell of the black holding tank throughout. Any ideas why? is the ac sucking in air from the tank vent?
Without ac running but the vent over the stove running or the fantastic fan running, do you smell holding tank odor?
__________________


2016 Siverback 33IK, Towed 50K+ mile
2018 Ford F-350 Lariat 6.7L V8 Diesel 4WD Crew Cab

"If you don't know where you are going, any road will get you there."
dalford is offline   Reply With Quote
Old 08-11-2018, 11:45 PM   #17
Senior Member
 
Join Date: Apr 2016
Location: Port Charlotte Fl/Hinsdale Ma
Posts: 4,823
Quote:
Originally Posted by JohnD10 View Post
It is also possible that your roof vent for the black tank is located near an AC unit, which may be pulling the fumes from the vent back into the RV through the AC.

There are alternatives to the stock roof vents available.
The RV roof AC does not draw air in from the outside. It only recirculates the inside air. Your house AC works the same way. Auto AC can draw in outside air.
the smell is coming from an air admittance valve under a sink in the coach.
cavie is offline   Reply With Quote
Old 08-12-2018, 03:53 AM   #18
Senior Member
 
DouglasReid's Avatar
 
Join Date: Jun 2016
Location: Maurice, LA
Posts: 4,095
Quote:
Originally Posted by chapelt View Post
if your smelling something in your unit with the A/C running, then the odor is coming from inside the unit.
When was the last time you took the cover off the AC unit and cleaned the coils and the drip pan?

Im guessing the answer is never.
__________________
2012 Wildcat Sterling 32RL, Gladiator Qr35 ST235/85R16 Load rating G, TST 507 TPMS w/ Flow-thru Sensors & Repeater, Reese Sidewinder 16K Pin Box, PI EMS HW50C
2009 Chevy Silverado 2500HD CCSB LTZ Diesel, Fumoto Oil Drain Valve, Turbo Brake activated, 39 gal Aux Tank W/ Fuel Pump transfer, Air Lift Loadlifter 5000 air bags.
DouglasReid is offline   Reply With Quote
Old 08-12-2018, 06:25 AM   #19
"On the road again"
 
rjshiflet's Avatar
 
Join Date: Feb 2012
Location: Parker County Texas
Posts: 1,152
We had this issue with our 2017 Cardinal and I was advised (by someone in this forum -thank you) to get on the roof...pull the vent covers off by removing a small Phillips screwdriver and use the expanding foam spray insulation AROUND the vent pipe. Replace the vent cover and put a dab of silicone to seal the screw back in and you're done.

I did - problem solved.

While the outside AC units may not pull air in from the outside...the odor can escape from the vent tube then be pulled back between the roof and insulation and get into the AC's return air that way.

I added spray foam insulation around ALL of my vent pipes and we haven't had the problem since.


Here's another thread on the subject: http://www.forestriverforums.com/for...l-73081-2.html
__________________


Robert & Estha Shiflet
Georgetown XL 378TS
Jeep Gladiator Willys Tow Vehicle
rjshiflet is offline   Reply With Quote
Old 08-12-2018, 08:30 AM   #20
Senior Member
 
Join Date: Sep 2016
Location: Colorado
Posts: 1,306
Haven't had the problem, but interested in what you find. First trick would be to use anti stink in the holding tank, but wouldn't do that until you find the source of odor penetration.
__________________
2003 Duramax
2017 Crusader 315

2016 Boston Whaler Montauk 150
Former Montana owner
Colorado Cruiser, Over the Pass and Down the Hill
Comanchecreek is offline   Reply With Quote
Reply

Tags
black, black tank, tank

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Forest River, Inc. or any of its affiliates. This is an independent, unofficial site.



All times are GMT -5. The time now is 07:20 AM.