Reply
 
Thread Tools Display Modes
Old 10-18-2017, 05:49 PM   #1
Member
 
Join Date: Jul 2017
Posts: 43
Kitchen sink drain issues

My kitchen sink drains amazing for the first 7 gallons. Then just stops. My only options to get the sink to drain at the point is to either (1) open the galley dump valve or (2) unscrew the vacuum break under the sink.
Note, when I open the vacuum breaker, a lot of vapor rushes out around the threads.
This suggests that there is simply too much back-pressure on the drain line. Once the tank is depressured, I can drain another 7 gallons, and the problem repeats itself.

I stuck a hose down the roof vent and let water flow down the vent pipe for an hour. I could not close the galley drain valve for more than a few minutes. Otherwise the galley tank level indication went to 100%. So the vent is apparently not clogged (as I original assumed).
I'm stumped, any advice ???

2018 Forest River Cardinal 3350RL
We dry-camp half the time. So leaving the tank drain open is not an solution when boondocking.
__________________

Daniellekristopher is offline   Reply With Quote
Old 10-18-2017, 10:24 PM   #2
Senior Member
 
Join Date: Oct 2015
Posts: 390
It still sounds like a venting issue. The vent pipe could stick down into the tank and so water will run thru it but will allow it to back up fast. Can you stick a camera in there to check it?
__________________

__________________
Dale & Karen
2015 Lacrosse 311RLS
2006 F-250 The 06-6.0
Dwilcox is offline   Reply With Quote
Old 10-18-2017, 10:52 PM   #3
Senior Member
 
SlfMdeFam's Avatar
 
Join Date: Oct 2017
Location: SoCal
Posts: 463
Quote:
Originally Posted by Daniellekristopher View Post
My kitchen sink drains amazing for the first 7 gallons. Then just stops. My only options to get the sink to drain at the point is to either (1) open the galley dump valve or (2) unscrew the vacuum break under the sink.
Note, when I open the vacuum breaker, a lot of vapor rushes out around the threads.
This suggests that there is simply too much back-pressure on the drain line. Once the tank is depressured, I can drain another 7 gallons, and the problem repeats itself.

I stuck a hose down the roof vent and let water flow down the vent pipe for an hour. I could not close the galley drain valve for more than a few minutes. Otherwise the galley tank level indication went to 100%. So the vent is apparently not clogged (as I original assumed).
I'm stumped, any advice ???

2018 Forest River Cardinal 3350RL
We dry-camp half the time. So leaving the tank drain open is not an solution when boondocking.


Plumber here... most likely what is happening is the drain pipe from the sink to the tank has a negative back grade on the pipe, not a gradual down hill slope towards the tank. Once you have enough water in the drain it creates air lock and the vacuum breaker(most likely not working properly either) not opening is causing this to happen. Hope that helps.
SlfMdeFam is offline   Reply With Quote
Old 10-19-2017, 10:53 AM   #4
Member
 
Join Date: Jul 2017
Posts: 43
I thought about the vent pipe dropping. But would assume the design of the vent pipe would be larger than the tank connection. Vent pipe being the female. And tank connection being the male. But I can’t validate that without seeing it.
So your suggestion is very possible, and the most logical.
Unfortunately I don’t see a means to get to the tank without removing 50 bolts on the under-blanket. Ugh.
Daniellekristopher is offline   Reply With Quote
Old 10-19-2017, 10:59 AM   #5
Member
 
Join Date: Jul 2017
Posts: 43
Regarding the air-lock theory, with that issue I would get a vacuum at the vacuum breaker. But instead, I am getting a pressure-buildup. Air is coming out when I remove the vacuum breaker.
But I will still replace vacuum breaker just in the one-off that’ll fix it. I will report back in a few day.

Also, sometimes air violently erupts up throw the undrained water in the sink. Especially on a hot day.
Daniellekristopher is offline   Reply With Quote
Old 10-19-2017, 11:55 AM   #6
Head Rambler
 
Join Date: Mar 2008
Location: Southwest Alabama
Posts: 6,573
If air is 'bubbling' up in the sink, it's a vent issue. The fact that you get backflow of vapor out of the air admittance valve says that it's a vent issue also.

On most of those tanks, a hole is cut in the top of the tank and the vent pipe is just stuck in the hole and sealed up. there's nothing to keep it from being inserted too far except the technician's estimation.
__________________
Salem 29RKSS Pushing a GMC Sierra 2500HD!
Gotta go campin!
Bama Rambler is offline   Reply With Quote
Old 10-19-2017, 01:20 PM   #7
Member
 
Join Date: Jul 2017
Posts: 43
Thanks for the knowledge. I will get Into the tanks area over thanksgiving and reply with my findings and attach photos.
On the topic of the Cardinal 3350RL, I discovered while flushing water into the galley vent line that the Black Water tank and Galley grey water tank share a common vent. So it’s possible for black water vapors to flow into your kitchen if the P-trap losses water.
The bathroom grey water tank hasn’t it’s own vent.
Daniellekristopher is offline   Reply With Quote
Old 10-19-2017, 02:27 PM   #8
Senior Member
 
Thurman's Avatar
 
Join Date: Aug 2011
Location: Albany, GA.
Posts: 1,177
I will also state that you have a vent issue and the most likely cause in your case would be the vent stack (pipe) is into the tank too far.
Thurman is offline   Reply With Quote
Old 10-19-2017, 03:05 PM   #9
Senior Member
 
CaptnJohn's Avatar
 
Join Date: Dec 2015
Location: Eastern NC
Posts: 3,593
Quote:
Originally Posted by Thurman View Post
I will also state that you have a vent issue and the most likely cause in your case would be the vent stack (pipe) is into the tank too far.
X 2 and quite common.
CaptnJohn is online now   Reply With Quote
Old 10-19-2017, 03:12 PM   #10
Senior Member
 
SlfMdeFam's Avatar
 
Join Date: Oct 2017
Location: SoCal
Posts: 463
I’m willing to bet after you replace the vacuum breaker it’ll drain fine
__________________

SlfMdeFam is offline   Reply With Quote
Reply

Tags
drain, sink

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.




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 01:27 PM.