Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 03-11-2016, 12:03 AM   #1
Senior Member
 
mojoracing's Avatar


 
Fleetwood Owners Club
Ford Super Duty Owner
Join Date: Oct 2013
Location: northern IL
Posts: 2,557
Grey tank drains slowly

I have had a problem lately with draining our grey tank. While hooked up to the sewer via standard type stinky slinky, I wait until grey is 2/3 or more and then go to drain the tank. I pull the valve and it starts to drain normally but then slows down after a few seconds to almost a trickle like its empty. At times I can hear a hissing noise like the tank is trying to take in air from a vent or small opening perhaps from the drain hose coupling (not a big enough gap to leak water but enough to try and suck some air when vacuum is caused by draining). Eventually, it overcomes the vacuum that formed and there is another woosh and then it slows down again to a trickle and sometimes does it a third time until the tank is finally drained. Could this be an issue with this particlular sewer I am hooked up to or is it a problem with the tank venting. Would it be the roof vent (which I doubt is plugged as the MH is fairly new and has done this to one extent or another since new) or perhaps the vacuum breaks under the sinks not working right? Not sure if the vacuum breaks even have anything to do with it. I asked once before and someone said it might be a disk left in the tank when they drilled the opening in the tank but this is definitely a vacuum problem that developes.
__________________

__________________
2014 Fleetwood Bounder 35k
mojoracing is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 03-11-2016, 12:30 AM   #2
Senior Member
 
Mr_D's Avatar
 
Solo Rvers Club
iRV2 No Limits Club
Join Date: May 2011
Location: Vancouver, WA
Posts: 28,477
Something like a cutout being sucked in to the tank drain? Sometimes when they cut the holes the cut out piece gets left in the tank and can get sucked up and into the outflow.
__________________

__________________
2009 45' Magna 630 w/Cummins ISX 650 HP/1950 Lbs Ft
Charter Good Sam Lifetime Member, FMCA, SKP
RV'ing since 1957, NRA Benefactor Life, towing '14 CR-V
Mr_D is offline   Reply With Quote
Old 03-11-2016, 12:40 AM   #3
Senior Member
 
mojoracing's Avatar


 
Fleetwood Owners Club
Ford Super Duty Owner
Join Date: Oct 2013
Location: northern IL
Posts: 2,557
Like I said at the end of my statement, not the disk problem. Im almost 100% sure of it. I can hear the tank trying to take in air to vent it. Seems like once it takes in enough air, it breaks the vacuum and WHOOSH, it drains normal again until it needs to take air in again.
__________________
2014 Fleetwood Bounder 35k
mojoracing is offline   Reply With Quote
Old 03-11-2016, 06:28 AM   #4
Senior Member
 
Tha_Rooster's Avatar
 
Join Date: Aug 2008
Location: Georgia
Posts: 4,517
On mine the grey pipe is half the size of the black and drains slower.
__________________
2007 Fleetwood Revolution LE 40V
Tha_Rooster is offline   Reply With Quote
Old 03-11-2016, 06:33 AM   #5
Senior Member
 
jacwjames's Avatar
 
Monaco Owners Club
Join Date: Jun 2014
Posts: 4,597
I would think that if you primary vents are a problem the water would pull the water out of one of the "Pee" traps. You might try actually removing one of your Pee traps to create a completely open vent. If you still have a problem it rules out a vent issue.
__________________
Jim J
2002 Monaco Windsor 38 PKD
2005 Jeep Grand Cherokee w/5.7 Hemi
jacwjames is offline   Reply With Quote
Old 03-11-2016, 06:45 AM   #6
Senior Member
 
Triker56's Avatar
 
Fleetwood Owners Club
Join Date: Jun 2009
Posts: 3,948
Check your roof vent for wasp nest. Your 14 model could have been built in 2013 and that is enough time for them to build nest.

Take a water hose to the roof and flush the vent out good.
__________________
99 Discovery 34Q ISB
2014 MKS AWD EcoBoost Toad
Fulltime Since "99"
Triker56 is offline   Reply With Quote
Old 03-11-2016, 06:56 AM   #7
Senior Member
 
Join Date: Nov 2015
Posts: 4,080
As liquids go into a waste tank air has to be expelled.
When liquids are drained out of a waste tank air has to come back in.

You have a clogged/obstructed roof vent......bird nest/mud dabbers/crushed vent cap etc.

The Air Admittance Valve under kitchen & bathroom sinks are to keep 'p' traps from getting sucked dry when draining grey tank.
They have small opening just enough to allow air in but limited volume.......no where near enough to keep up with full vented needed when draining grey tank---just enough that water in 'p' trap stays put.

Need to go up on roof----remove grey tank vent cap and run a garden hose down inside vent line as far as you can then with grey drain valve open..blast away.

If that doesn't resolve your slow tank draining issue........
Then you have a cut-out disc left inside tank and it gets sucked down to outlet.

I bet........roof vent line obstructed
__________________
Old-Biscuit is offline   Reply With Quote
Old 03-11-2016, 07:10 AM   #8
Senior Member
 
mojoracing's Avatar


 
Fleetwood Owners Club
Ford Super Duty Owner
Join Date: Oct 2013
Location: northern IL
Posts: 2,557
Thanks guys, after pondering this I think you are right. The roof vent is probably obstructed. I know its not the disk thing just by the way it acts. I thought maybe the vents under the sink because I had to replace them when they went bad and I was getting a smell. Thought perhaps they had a different opening pressure than the stock ones but now I now they do not contribute hardly anything to the actual venting of the tank. I just hope its something like a wasp nest and not an issue with the way the coach was built. I have heard of vent lines being installed too low in a tank and such.
__________________
2014 Fleetwood Bounder 35k
mojoracing is offline   Reply With Quote
Old 03-11-2016, 07:18 AM   #9
Senior Member
 
Join Date: Nov 2015
Posts: 4,080
Quote:
Originally Posted by mojoracing View Post
Thanks guys, after pondering this I think you are right. The roof vent is probably obstructed. I know its not the disk thing just by the way it acts. I thought maybe the vents under the sink because I had to replace them when they went bad and I was getting a smell. Thought perhaps they had a different opening pressure than the stock ones but now I now they do not contribute hardly anything to the actual venting of the tank. I just hope its something like a wasp nest and not an issue with the way the coach was built. I have heard of vent lines being installed too low in a tank and such.

When you remove roof vent cap check where end of vent line is........should be almost even/slightly below roof line.
If dropped down...grab with vise grips and see if you can pull back up then secure with couple of wood screws thru wall of pipe into roof structure then calk over screws.
__________________
Old-Biscuit is offline   Reply With Quote
Old 03-11-2016, 03:22 PM   #10
Senior Member
 
Join Date: May 2014
Posts: 2,796
It could be something as simple as your drain hose is just not on as good of a slope it should be when draining. Sometimes ours does the same thing but I pick up the last part of the hose just as it goes into the CG drain and there is water stuck in that last foot or so where it dips, creating kind of a back pressure. Once I get that water flowing again you hear the big whoosh and the rest drains fairly quick.
__________________
Mike & Charlotte
2014 Newmar Canyon Star 3610
Orange County, California
Mike and Cha is offline   Reply With Quote
Old 03-11-2016, 03:59 PM   #11
Senior Member
 
TonyMac's Avatar
 
Monaco Owners Club
Join Date: Oct 2014
Location: Layton, Utah
Posts: 995
Quote:
Originally Posted by jacwjames View Post
I would think that if you primary vents are a problem the water would pull the water out of one of the "Pee" traps. You might try actually removing one of your Pee traps to create a completely open vent. If you still have a problem it rules out a vent issue.
Ditto on the pee trap. If the suction got a bit strong the pee traps would start gurgling. You got something in your tank. It's a new rig? Even more sure now.
__________________
TonyMac is offline   Reply With Quote
Old 03-12-2016, 01:44 PM   #12
Senior Member
 
Belgian's Avatar
 
National RV Owners Club
Join Date: Jun 2006
Location: Manhattan Beach, CA
Posts: 618
Don't stick a hose down the vent pipe if it has the threaded ends on the hose. I have seen more people get their hose stuck in some pipe they were trying to clean out and can't get the hose out once it makes even the slightest turn.
It is possible that the roof vent pipe has fallen too far into the grey tank.

it could be the drain at the CG you are hooked up to also.
__________________
Steve & Jeri
2004 Dolphin 5342
2000 Jeep Cherokee 4X4
Belgian is offline   Reply With Quote
Old 03-12-2016, 04:02 PM   #13
Member
 
Join Date: Mar 2013
Posts: 87
Pretty normal if you open the valve all the way all at once. Try opening it up less and wait more.
__________________

__________________
STORMY 1 is offline   Reply With Quote
Reply

Tags
tank



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Black & Grey Drains ? rideandslide Travel Trailer Discussion 4 11-30-2015 01:18 PM
Shower Drains Slowly RealDeal440 5th Wheel Discussion 9 09-10-2011 09:30 PM
Shower Drains Slowly RealDeal440 Travel Supreme Owner's Forum 3 08-30-2011 10:32 AM
shower drains slowly DonnaB Newmar Owner's Forum 12 09-10-2008 08:35 PM
shower drains slowly RV Systems & Appliances 12 12-31-1969 07:00 PM

» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 08:33 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.