Thread Tools Display Modes
Old 05-01-2014, 11:02 AM   #1
Join Date: Jan 2014
Posts: 77
Black tank flush

I just tried to use the black tank flush for the first time. Is there some sort of trick? The water will not flow into the tank.

Preadus is offline   Reply With Quote
Old 05-01-2014, 11:26 AM   #2
Senior Member
Campin Cajun's Avatar
Join Date: Mar 2013
Location: Cut Off, La.
Posts: 1,830
There should be a check valve somewhere along that water line. Yours might be installed backwards. I'm not familiar with the wetbay on that model, on my Berkshire the access is on the PS and I can see the black tank there. The washer is held on by three screws, if yours is the same take the screws out, pull the washer out and see if you are getting water to it.

2013 Berkshire 390BH
Campin Cajun is offline   Reply With Quote
Old 05-01-2014, 12:01 PM   #3
Senior Member
bubbles's Avatar
Join Date: Dec 2012
Posts: 1,799
I have a GT378 and the backflow valve is in the washing machine provisional area and zip tied to the plumbing for that washer. If you have emptied your black tank before and not ran water thru the cleanout the nozzle for that cleanout may be cloged with tank residue. If you locate the backflow valve and it's a clear one as is mine you will see how it is supposed to operate. It's just a simple water pressure switch.
bubbles is offline   Reply With Quote
Old 05-01-2014, 03:46 PM   #4
Senior Member
Iggy's Avatar
Join Date: Jul 2010
Location: Desert SW - Arizona
Posts: 5,887
Looks like this inside one of the bedroom closets and may be behind a piece of wood panel. Usually close to where the washer dryer is hooked up at.
Attached Thumbnails
Click image for larger version

Name:	$_57.jpg
Views:	144
Size:	61.1 KB
ID:	51373  
2012 Georgetown XL - 378TS 49,000 miles
(2013 - 98 days) (2014 - 117 days) (2015 - 67 days) (2016 - 115 days)
USAF Retired - MSgt

Iggy is offline   Reply With Quote
Old 05-06-2014, 10:21 AM   #5
Join Date: Feb 2014
Posts: 74
I have the same issue. Did you ever correct yours?
k3wtf is offline   Reply With Quote
Old 05-06-2014, 10:46 AM   #6
Junior Member
Join Date: Mar 2014
Location: Texas
Posts: 6
This is a Vacuum Breaker required by Code to prevent the possible siphoning of contaminated liquids back into the water supply. If the Breaker is installed with the bonnet in the up position, it should work as designed and allow water to flow into the dark water tank.
Texas Peddler is offline   Reply With Quote
Old 05-06-2014, 06:22 PM   #7
Join Date: Jan 2014
Posts: 77
I have a scheduled repair. I'll let you know what they say.
Preadus is offline   Reply With Quote
Old 05-06-2014, 06:39 PM   #8
Senior Member
Mark S's Avatar
Join Date: Feb 2012
Posts: 234
How fast should water flow into tank? Mine goes in but seems like a seems slow, not like when I use the discharge valve flush. Should water trickle out of the tank when flushing or a fast flow?
Mark and Joanne
2014 Fun Finder XT 276
2015 Ford F150 Lariat 3.5 Ecoboost 4X4 SCrew Max Tow
2011 Harley Road Glide Ultra
Mark S is offline   Reply With Quote
Old 05-06-2014, 08:29 PM   #9
Join Date: Mar 2014
Posts: 82
I tried the black tank flush on my last trip....I have a new GT 328. If you just plug the hose in, have the black tank valve open, and turn on the hose, the water comes out in a steady stream, but without the large "swoosh" that you get when you open that big valve with a full tank. I closed the valve, let the tank level build up, and then opened the valve. I did that a few times, then I turned off the flush hose, closed the black valve, and opened the grey valve. I don't know if I did it exactly correctly, but it seemed to work.
Scagsdale is offline   Reply With Quote
Old 05-07-2014, 07:14 PM   #10
Senior Member
ramair's Avatar
Join Date: May 2012
Location: Texas
Posts: 609
that's the way I flush mine. I do this until clear water only comes out.

Andrew & Donna Reyes
2012 Georgetown 378XL
2015 Ford Taurus
Our Baby Dachshund
ramair is offline   Reply With Quote

black, black tank, black tank flush, 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

» Virginia Campgrounds

Reviews provided by is not in any way associated with Forest River, Inc. or its associated RV manufacturing divisions.

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 12:34 AM.