Go Back   Montana Owners Club - Keystone Montana 5th Wheel Forum > GENERAL DISCUSSIONS > General Discussions about our Montanas
Click Here to Login

Thread Tools Display Modes
Old 10-21-2017, 09:23 PM   #21
Montana Master
Join Date: Oct 2006
Location: McKinney
Posts: 5,252
M.O.C. #6433
I agree with you that it is highly unlikely black water can come back out the inlet. But it is not there to protect against an over full tank. Antisiphon valves are required in any application where a loss of supply water line pressure and the resulting siphoning occurs that can suck all the water back out of an open line. Think of when you lose water pressure at home and you end up with air in all your water lines because the water was siphoned out due to the negative pressure being pulled. But home inside water connections have no direct connection to contaminated water and an antisiphon valve is not required. But if you have a lawn sprinkler system it requires an antisiphon valve as it could suck dirty water back into the line.

The only way a black tank flush could send contaminated water back into the water supply lines is if you had no antisiphon valve, the spray head was or had been immersed in black water, you started doing a flush, and the water supply suddenly lost pressure and began pulling a vacuum on the line and sucking that water out of that line. The odds of all that coming together are very slim. Slim but possible.
Bill & Patricia

2007 3075RL
2012 F350 SRW CC LB FX4 6.7
BB_TX is offline   Reply With Quote
Old 10-22-2017, 07:38 PM   #22
Montana Master
beeje's Avatar
Join Date: Oct 2015
Location: westminster md
Posts: 1,353
M.O.C. #17894
I agree that is entirely possible (but un likely), when I flush mine out (like most others) I am standing right there listening and observing what is happening. I would more than likely notice the reduction of water pressure flowing in. I suppose in the politically correct world we live in a backflow preventer would be in order.
beeje is offline   Reply With Quote

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 Montana RV, Keystone RV Company or any of its affiliates. This is an independent, unofficial site.

All times are GMT -6. The time now is 08:27 PM.

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2019, vBulletin Solutions, Inc.