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

Go Back   Keystone RV Forums > Keystone Tech Forums > Repairs & Maintenance
Click Here to Login

Thread Tools Display Modes
Old 08-11-2022, 07:35 AM   #21
Senior Member
Join Date: Sep 2019
Location: Jonesboro
Posts: 374
Full-way valve is another way of saying black tank dump valve.

Having it open to dump position is a safe way to keep you from turning on flush water and forgetting or becoming distracted itís on.
Many RVíers have turned it on, then left dump valve closed, black tank fills up and toilet overflows into camper.
2020 Cougar 29RKS 31ft Fifth Wheel
2019 F350 4WD Lariat SRW 6.7 Diesel
Anderson Ultimate 5th Wheel Hitch - TST509 TPMS
2200W(8)Solar Panels (6)100AH BattleBorn Lithium Batteries. 3000W Victron MultiPlus Inverter
SoftStartRV on both ACís - Predator 3500 generator
rlh1957 is offline   Reply With Quote
Old 08-11-2022, 07:49 AM   #22
Camp CA
Senior Member
Join Date: Jan 2020
Location: Benicia, California
Posts: 284
Ditto rlh1957.........recommend connecting the black tank flush hose ONLY when adding water to the holding tank AND during tank flushing/dumping, otherwise keep it disconnected from the rv flush connection. Yhis mitigates the risk of wwater leaking through the valve and overfill the black tank.
2020 Montana 3780RL fifth wheel
2016 F-350 Crew Cab long bed DRW 6.7L Diesel
Camp CA is offline   Reply With Quote
Old 08-11-2022, 09:26 AM   #23
Island Eddie
Senior Member
Island Eddie's Avatar
Join Date: Jun 2020
Location: clinton
Posts: 347
Lots of good advice and a proper maintained drain and waste system is essential for a good camping experience.

The reason I brought up the "closed" valve when filling from this flush connection was because some have talked about the anti-syphon leaking when using this connection. I have read where others said they removed it from the water line....

If a person needs to be told that leaving it closed when filling will overflow the toilet, perhaps they need to be told not to go back to their trailer to make a cup of coffee while still driving down the highway

These anti-syphon valves are CHEAP, extremely cheap, from one who has spent his whole working life as a plumber and dealing with backflow prevention.
A kink in the pex going to the black tank, or an obstruction in the line at the black tank, even a small wad of toilet paper, or a kernel of corn off that cob wedged just so....can cause back pressure and make the valve "spill over"

It's doing as designed, just poorly.

Why I mentioned the tank valve being closed, it presents back pressure too, as the tank fills, like blowing up a balloon, the more air you blow into the balloon, the harder it gets to expand....

Also, most trailers I believe have "mechanical vents" not open to the atmosphere like our house, they work by "emitting" air into the system to allow for drainage without sucking the traps dry under the fixture. They use these because our vent terminals are so close to our open windows, camping area outside, where the fumes could easily encompass us with their stench....
So they "close" too when back pressure is exerted on it, like filling the black tank quickly with the flushing hose.

Moral of the story....if your flushing system leaks when using, try leaving the valve open, using less pressure in the water hose feeding it, and see if that helps.

Class dismissed
Island Eddie is offline   Reply With Quote

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
Forum Jump

Powered by vBadvanced CMPS v3.2.3

This website is not affiliated with or endorsed by the Keystone RV Company or any of its affiliates in any way. Keystone RVģ is a registered trademark of the Keystone RV Company.

All times are GMT -8. The time now is 05:28 PM.

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2022, vBulletin Solutions, Inc.