If you're having issues with it, others have cut the pex and installed two 90's and a small pex section effectively eliminating the valve altogether. That might be able to be done down low where the pex lines are accessible. Personally, I would go that route instead of tearing my shower off the wall. Just my .02
Sorry; do not follow this advice.
You will siphon black water out of the tank when traveling down the road (due to Venturi Effect) and you can get black water bacteria into the fresh water source due to mixing of the incoming water and the water in the black tank. This can happen due to pressure fluctuations in the source and pressure changes when starting and stopping the water flow.
The backflow preventer/Vacuum Break is required and can be relocated but NOT eliminated.
(Perhaps you were thinking of the water FILTER, which can be eliminated as you describe).
I don't know how (YOU) hook up your (Black Tank Rinse) but most have a (Garden Hose Fitting) that people hook up a (Fresh Water Hose ) I would call this (Connected)! I also have a Very good Idea who has Not a Clue! Youroo!!
Youroo it's looks like you, you got one HA, Spam up to $3.35 a can
I've been here for over 3 years now, and have monitored this forum pretty closely. I'm a little confused about all the sudden interest and/or concern over black tank flush anti-siphon valves. I have seen very little on this until this past month. Is there something which every TT and 5'er owner needs to do that we've all not been doing, either in normal operation or winterization, which someone here can state simply for the benefit of those who may be scratching their heads reading all of these posts (even if "those" is only me!)? I'm afraid I may be missing the point.
You will siphon black water out of the tank when traveling down the road (due to Venturi Effect) and you can get black water bacteria into the fresh water source due to mixing of the incoming water and the water in the black tank. This can happen due to pressure fluctuations in the source and pressure changes when starting and stopping the water flow.
The backflow preventer/Vacuum Break is required and can be relocated but NOT eliminated.
(Perhaps you were thinking of the water FILTER, which can be eliminated as you describe).
Herk why can't you just add a 1/2" back flow preventer?
You can; BUT ---
Vacuum breaks are normally used in this application (AND dishwasher discharge lines for the same reason) to create an air path into the black tank should there be a negative (suction) pressure during the dump cycle.
Without the vacuum break (ie using a check valve like some cheap after market "turbo flushers" include), the dump negative pressure can "flutter" the check valve (ever watch the water flow at the dump outlet using a clear elbow?) potentially allowing bacteria on the dirty side of the valve to enter the fresh (campground side) water source.
Backflow preventers are "inline" and Vacuum breaks are always an "elbow" with a hat.
ALSO note that the inline backflow preventer dumps its pressure through the outlet holes! If this is INSIDE your camper there will be water everywhere.
(NOTE: NOT a plumber; but this is how I understand it.)
__________________
Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
Vacuum breaks are normally used in this application (AND dishwasher discharge lines for the same reason) to create an air path into the black tank should there be a negative (suction) pressure during the dump cycle.
Without the vacuum break (ie using a check valve like some cheap after market "turbo flushers" include), the dump negative pressure can "flutter" the check valve (ever watch the water flow at the dump outlet using a clear elbow?) potentially allowing bacteria on the dirty side of the valve to enter the fresh (campground side) water source.
Backflow preventers are "inline" and Vacuum breaks are always an "elbow" with a hat.
ALSO note that the inline backflow preventer dumps its pressure through the outlet holes! If this is INSIDE your camper there will be water everywhere.
(NOTE: NOT a plumber; but this is how I understand it.)
I do understand what you are saying but that is not the one I meant. I mean a brass blackflow preventer, the same as the VDH requires on a water line from the town water supply, so my well water can not enter the city system if I use the well water instead of town water. There really is no vacuum that can happen when in use being that the dump valve is open. When not using it the back flow preventer would stop anything entering the line before it. I hope I'm explaining this correctly. My fresh water inlet and my BTF are two different lines, it would still stop any black flow to your hose that you are using to do the flush. I hope it makes sense to you, my explanation. Your pictures shows faucet back flow preventers not in line. It would be hard to over come the PSI at a camp ground to contaminate the CG water system.
Just cut the lines to the one you can't get to, splice in new lines and put the new one where you can get to it. Problem solved.
It is not rocket science.
Just cut the lines to the one you can't get to, splice in new lines and put the new one where you can get to it. Problem solved.
It is not rocket science.
No it is not but without changing my whole system it can not be done where FR installed mine. The only safe feature is that it is in between the wall and shower but impossible to get to with out me putting in a access panel in my bedroom wall, and my wife's not going for that or removing a shower which then would leak. I do understand this is not rocket science. But I do care about my environment.
pictures shows faucet back flow preventers not in line.
They do not. Both "hat" photos are of RV turbo-flush vacuum breaks.
The black one is MY vacuum break under my vanity.
The clear one actually shows the "guts" of the double internal check valves.
The two brass ones are the inline check valves you refer to and contain a plastic valve.
Your PDF is similar to the brass ones noted; they just have NPT threads instead of hose fitting threads.
__________________
Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
They do not. Both "hat" photos are of RV turbo-flush vacuum breaks.
The black one is MY vacuum break under my vanity.
The clear one actually shows the "guts" of the double internal check valves.
The two brass ones are the inline check valves you refer to and contain a plastic valve.
Your PDF is similar to the brass ones noted; they just have NPT threads instead of hose fitting threads.
Yes but the two brass you show would leak, that is there purpose. So they are not an option. The one I showed has a stainless steel spring with a brass flapper and will not leak like a hose bib that you showed. That go's on a hose bib only not in a enclosed wall. You really do not need a vacuum valve. When you open your valve there can't be a vacuum also the tank has a vent pipe to stop that also. Dumb, Dumb of FR. If it is required by the health dept code they should have installed brass. Just IMO.
Mine is located under the bathroom sink and can just barely be reached. It has only leaked a couple times in the last year while dumping the black tank and using the tank wash. I assume it did it's job and was due to a vacuum being created due to whatever combination of variables occurred at that time. The amount of water was minor and easily noticed while dumping. I'm not positive of the sequence that caused the leak but it may have been that I turned the wash on too early while the tank outlet was flowing full thereby creating the vacuum.
It sure is in a bad location though, but I assume it needs to be located higher than the toilet. If I ever have to replace it, I will just cut both lines where they turn vertical and splice them back after replacing the valve.
__________________
2014 Ford F250 Lariat
2014 Rockwood Signature Ultra Lite 8280 WS
2023 Forest River Rpod model 201
Louisiana before, fulltiming since April 11, 2014
blog--- www.gozatravels.blogspot.com
Mine is located under the bathroom sink and can just barely be reached. It has only leaked a couple times in the last year while dumping the black tank and using the tank wash. I assume it did it's job and was due to a vacuum being created due to whatever combination of variables occurred at that time. The amount of water was minor and easily noticed while dumping. I'm not positive of the sequence that caused the leak but it may have been that I turned the wash on too early while the tank outlet was flowing full thereby creating the vacuum.
It sure is in a bad location though, but I assume it needs to be located higher than the toilet. If I ever have to replace it, I will just cut both lines where they turn vertical and splice them back after replacing the valve.
What I still do not understand is that there is a vent tube and your dump valve is open. How can it cause a vacuum? If your dump valve was closed during travel even then how can you pull a vacuum with the vent pipe to the tank unless it was plugged.... It is impossible to pull a vacuum with a vent pipe. The spray nozzle's are so small how can it even return to that line that the loop is above the toilet. That is also why washing machine drains are higher then the outlet. There is also a warning stating do not run the BWF with the valve closed. I guess by code they have to install it.
Same reason there are vacuum breakers on lavatory and sink drains in houses. Keeps from syphoning the P traps dry. Most lavatories and tubs have what are mistakenly called overflows but are actually vacuum breakers.
I think OC has the right approach when using the word "siphoning". However; siphoning ( I believe) requires that one end be submerged and a differential pressure applied to the other end to get started. My cleanout sprayer is at the top of my black tank and is never below water level and the input side of the cleanout is enclosed behind a cargo hatch where there is no airflow across it while traveling. Additionally, my backflow plumbing has a 5 foot rise above the tank. I think "code" is the optimal word here. JMO.
Youroo!!
It is impossible to pull a vacuum with a vent pipe. The spray nozzle's are so small how can it even return to that line that the loop is above the toilet. That is also why washing machine drains are higher then the outlet. There is also a warning stating do not run the BWF with the valve closed. I guess by code they have to install it.
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