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 07-22-2017, 10:40 AM   #1
Junior Member
 
Join Date: Nov 2016
Posts: 2
Black Tank Chimney Vent Blockage

My rig is a 2010 Palomino Puma 259RBSS. About a month ago, I let two sets of guests stay in it, using all facilities, and figured I would just hold off on dumping black and grey tanks for a few weeks before a long outing of our own.

I started noticing black tank smell in the bathroom itself, which used to not happen. I've heard that sometimes effluent material can dry and block sensors and vents, and that's my current theory of what's happening. On the roof, I smell nothing at the top of the vent pipe. Peering inside I see no visible blockage -- just spiderwebs.

Currently on a long road trip, and an RV dealer recommended using Commando in the tank about half-full, and actually dump in 4-5 bags of crushed ice before hitting the road. The chemicals plus slosh plus ice chunks should dissolve and knock away any blockage. So far, no luck.

I know the sensor is blocked because I had the tank FULL yesterday (added too much fresh water for the above solution) and the black tank level panel stayed on Empty.

With all of that, here are the questions:
  1. Under normal operation, how much black tank smell should one notice at the top of the vent pipe on the roof?
  2. What else should I try to free up the vent pipe so fumes can escape the way they're supposed to?
Thanks!
Tom
tlharv is offline   Reply With Quote
Old 07-22-2017, 10:50 AM   #2
Senior Member
 
Join Date: Jun 2012
Posts: 10,907
#1 - Don't know, I've never climbed up to smell it!
#2 - Put a hose down the vent if you can.
__________________
1988 Coleman Sequoia - popup (1987-2009) - outlasted 3 Dodge Grand Caravans!
2012 Roo19 - hybrid (2012-2015)

2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado 1500 Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10
rockfordroo is offline   Reply With Quote
Old 07-22-2017, 10:56 AM   #3
Senior Member
 
Join Date: Jul 2010
Location: Waynesville
Posts: 14,428
My WAG is your vent pipe is to close to the bottom of Black tank,below fluid level,not allowing gas/smell to rise! Drain black tank,let sit for short period of time "Dry" then go up and smell! If it has the Odor you are looking for the Pipe in too far down in tank! Your call! Youroo!!
__________________
youroo is offline   Reply With Quote
Old 07-22-2017, 11:08 AM   #4
Senior Member
 
Join Date: Jun 2012
Posts: 10,907
Quote:
Originally Posted by youroo View Post
My WAG is your vent pipe is to close to the bottom of Black tank,below fluid level,not allowing gas/smell to rise! Drain black tank,let sit for short period of time "Dry" then go up and smell! If it has the Odor you are looking for the Pipe in too far down in tank! Your call! Youroo!!
And if you don't have a black tank flush with it's vacuum breaker valve, you MIGHT have to open the toilet valve to provide a vent path to drain the tank if the vent is indeed underwater.
__________________
1988 Coleman Sequoia - popup (1987-2009) - outlasted 3 Dodge Grand Caravans!
2012 Roo19 - hybrid (2012-2015)

2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado 1500 Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10
rockfordroo is offline   Reply With Quote
Old 07-22-2017, 12:13 PM   #5
Senior Member
 
Join Date: Oct 2015
Location: West Texas
Posts: 146
When connected to a dump port, open the black tank valve. Go up on the roof and stick a hose in the stack. Turn on the water. After a few seconds, the water should be draining out the sewer hose. If the water comes back up and out of the stack then you have a blockage. The water pressure might dislodge whatever is in there if anything.

Something else to check, in our Puma the vent stack is pretty close to the roof vent in the bathroom. Every now and then if the wind is just right we can get a whiff of black tank.
__________________
2018 Chevrolet 3500HD CCSBSRW
Duramax/Allison

Demco 18k Autoslide
2012 Puma Unleashed 356QLB toy hauler
Toys - CRF250X, CRF250R, CRF450R, TTR230, TRX250EX, STX-1500 jet ski
rmoore0852 is offline   Reply With Quote
Old 07-22-2017, 12:31 PM   #6
Site Team
 
Flybob's Avatar
 
Join Date: Oct 2014
Posts: 15,266
You said you saw spider webs in the Black tank vent, If there are enough of them they can cause a problem. Did the people using the RV possible have full hook ups and leave the dump valve open? RV toilets and holding tanks require some TLC as compared to home systems. You should always educate anyone using it that is not familiar with it.
__________________

2015 Freedom Express 248RBS
TV 2015 Silverado HD2500 Duramax
TST Tire Monitors
Honda 2000I + Companion
2 100W solar panels
Flybob is offline   Reply With Quote
Old 07-22-2017, 03:30 PM   #7
Senior Member
 
Join Date: Jun 2015
Location: Albuquerque
Posts: 1,222
Blocked vent

Our houseboat vent had two 90 degree turns with a horizontal run between them. Waste sloshed up into it and blocked it when it dried. When gases built up in the tank, it swelled the tank enough to bow two stout channel iron struts that held it. There was also nothing to keep the pipe from dropping into the tank and submerging. Once we replaced the tank and put a working vent in, it worked much better. You should be able to smell sewage from the pipe on top. We put a 8' extension on ours because people were sleeping on the roof of the houseboat within a few feet of the vent. Very noticeable. All the smells you're getting in the toilet, should be noticeable in the vent pipe. Easy to check, just drop your hose down the pipe. Just don't drink out of that hose ever again.
__________________
2009 Roo 21ss + 2007 Superduty 6.0
mnoland30 is offline   Reply With Quote
Old 07-22-2017, 03:53 PM   #8
Censored Member
 
Join Date: Dec 2015
Posts: 342
Quote:
Originally Posted by tlharv View Post
My rig is a 2010 Palomino Puma 259RBSS. About a month ago, I let two sets of guests stay in it, using all facilities, and figured I would just hold off on dumping black and grey tanks for a few weeks before a long outing of our own.

Thanks!
Tom
Major mistake allowing a full black tank to mellow for a few weeks. I seriously doubt there is anything wrong with the black tank vent.

I could be wrong but I think the black tank vent is to allow the black tank to drain freely. If the purpose of the vent was to dissipate odors every campground would probably smell like a sewer.
ManlyMan is offline   Reply With Quote
Old 07-22-2017, 04:11 PM   #9
Senior Member
 
Join Date: Jun 2012
Posts: 10,907
Quote:
Originally Posted by ManlyMan View Post
Major mistake allowing a full black tank to mellow for a few weeks. I seriously doubt there is anything wrong with the black tank vent.

I could be wrong but I think the black tank vent is to allow the black tank to drain freely. If the purpose of the vent was to dissipate odors every campground would probably smell like a sewer.
Hmm. Pit toilets usually have vents. While the vent certainly allows the tank to drain freely, I think it's also to provide a chimney effect to pull odors up the vent rather than up the toilet. Of course, running our vent fans kind of overpowers the vent pipe. I'm sure it's also there to allow the "stuff" to go down the toilet. If there were no vent, it would either not go down or would "burp" going down.
__________________
1988 Coleman Sequoia - popup (1987-2009) - outlasted 3 Dodge Grand Caravans!
2012 Roo19 - hybrid (2012-2015)

2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado 1500 Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10
rockfordroo is offline   Reply With Quote
Old 07-22-2017, 06:39 PM   #10
Senior Member
 
Join Date: May 2017
Location: NE Wyoming
Posts: 165
Quote:
Originally Posted by rockfordroo View Post
Hmm. Pit toilets usually have vents. While the vent certainly allows the tank to drain freely, I think it's also to provide a chimney effect to pull odors up the vent rather than up the toilet. Of course, running our vent fans kind of overpowers the vent pipe. I'm sure it's also there to allow the "stuff" to go down the toilet. If there were no vent, it would either not go down or would "burp" going down.
I believe if you have water in your toilet that provides a seal from gases in the black tank. Your vent fan on or off should not make a difference. The vent is supposed to do two things, #1 is to vent the gasses out of the black tank and #2 vent the tank when you drain it. If you drain the tank and experience a chug-a-lug sound the toilet is sealed and your vent is blocked. If it is slow to drain and speeds up when you flush the toilet, the vent is probably partially blocked. I do not have an answer for your level sensor.
Grumpy7159 is offline   Reply With Quote
Old 07-22-2017, 08:52 PM   #11
Senior Member
 
Join Date: Nov 2013
Location: crete,il /texas
Posts: 498
It's not likely the vent is plugged you could run water down the vent but it's more likely it's the " air admittance valve" under the bathroom sink is not working properly, homedopot has them #39230
Big Bill is offline   Reply With Quote
Old 07-22-2017, 09:08 PM   #12
Senior Member
 
Join Date: Jun 2012
Posts: 10,907
Quote:
Originally Posted by Grumpy7159 View Post
I believe if you have water in your toilet that provides a seal from gases in the black tank. Your vent fan on or off should not make a difference. The vent is supposed to do two things, #1 is to vent the gasses out of the black tank and #2 vent the tank when you drain it. If you drain the tank and experience a chug-a-lug sound the toilet is sealed and your vent is blocked. If it is slow to drain and speeds up when you flush the toilet, the vent is probably partially blocked. I do not have an answer for your level sensor.
You're correct about toilet seal when not using it, but the toilet doesn't provide a seal when you're flushing. And if air can't come out, water/stuff can't go down. And you don't usually do that with the tank drain open. (I was responding to the "why is there a vent?" question.)
__________________
1988 Coleman Sequoia - popup (1987-2009) - outlasted 3 Dodge Grand Caravans!
2012 Roo19 - hybrid (2012-2015)

2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado 1500 Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10
rockfordroo is offline   Reply With Quote
Old 07-23-2017, 09:19 AM   #13
Junior Member
 
Join Date: Nov 2016
Posts: 2
I think the Commando did its job. I had plenty of slosh going on and now there are fumes coming out of the chimney pipe. True, it is positioned right next to the bathroom vent fan but usually I have it pulling air out of the cabin, so fumes can't get in.

Today I'm at a full-service RV park so I'll drain the tank and rinse it as best I can. The level indicator still reads less than 1/3 full but it might be accurate... I'll know when I fill it with a hose from the roof.

Never ever letting a black tank sit idle again. Thanks everyone for your swift comments!

Tom
tlharv is offline   Reply With Quote
Reply

Tags
black, black tank, lock, tank, vent

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 03:14 AM.