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-   -   Black wash anti-siphon, anti-backflow valve ? (http://www.forestriverforums.com/forums/f15/black-wash-anti-siphon-anti-backflow-valve-127854.html)

13larry 03-02-2017 11:07 AM

Black wash anti-siphon, anti-backflow valve ?
 
Does anyone know where the black flush anti-siphon, anti-backflow valve is located in a Forester 3051?

Kirk S 03-03-2017 07:34 PM

I too would like to know if the 3051 has such a valve and where it is located. Common sense would put it first in line after the fresh water hose connection to the black tank wash. You wouldn't want that backing up into your water supply.

wana65stang 03-05-2017 06:42 PM

Quote:

Originally Posted by Netgain (Post 1434998)
I too would like to know if the 3051 has such a valve and where it is located. Common sense would put it first in line after the fresh water hose connection to the black tank wash. You wouldn't want that backing up into your water supply.

The black tank flush connection isn't even near the flesh water connection, so I don't see how it could back up into your water supply. I don't know where the flow back valve is on 3051 , waiting for answer also. :confused::confused:

itat 03-05-2017 07:21 PM

The black tank flush line is not connected to the city water line, nor should you use your city water hose to feed the black tank flusher.

The backflow preventer will likely be in a cabinet or somewhere immediately inside the MH where the external connection is. The line feeding the flusher should go up from the back side of external connection to the valve and then down to the black water tank.

So look on the inside where the connection port is located. It's often in a cabinet in the bathroom.

Kirk S 03-05-2017 07:21 PM

I realize the two connections are nowhere near each other on the 3051.The fresh water supply I was referring to is the water supply being used to flush the black tank. Backflow could be possible if the water supply was turned off while still connected to the black washout and another faucet on that same supply was opened elsewhere.The same reason anti-siphon valves are installed on sprinkler systems connected to a potable water supply.

Kirk S 03-05-2017 07:28 PM

Quote:

Originally Posted by itat (Post 1436691)
The black tank flush line is not connected to the city water line, nor should you use your city water hose to feed the black tank flusher.

The backflow preventer will likely be in a cabinet or somewhere immediately inside the MH where the external connection is. The line feeding the flusher should go up from the back side of external connection to the valve and then down to the black water tank.

So look on the inside where the connection port is located. It's often in a cabinet in the bathroom.

What water supply would you connect to the black tank flush line hose connector on the side of a 3051? The only supply I have is city water at a campground.
Or are you speaking of the hose in particular. I don't use the drinking water hose... just a green garden hose for that.

itat 03-05-2017 07:38 PM

Yup. I was talking about using a dedicated separate hose and it sounds like you are doing that. Does your MH not have a separate connection for the black tank flush? It should be isolated from the fresh water system.

Kirk S 03-05-2017 07:53 PM

Yes, separate connections on the opposite sides of the motor home. And I agree with the way you say an anti-siphon valve should be installed. Hoping it has one and that it was done correctly. Until I find out I may just use an external one.

SeaDog 03-05-2017 08:01 PM

most of the time when you use the flush you are at a dump station and the water connection there is not for potable use. You are correct to use a dedicated wash out hose mine is gray in color so I never get it mixed up. I agree with the other posters on the location of the back flow preventers

itat 03-05-2017 08:05 PM

1 Attachment(s)
I use an external blackflow preventer because the plastic one inside must have broken. The previous owner replaced it with a plastic 90* fitting. Based on what I've read here that's not unusual. Sorry the picture turns on its side.

wana65stang 03-06-2017 12:29 PM

Quote:

Originally Posted by Netgain (Post 1436692)
I realize the two connections are nowhere near each other on the 3051.The fresh water supply I was referring to is the water supply being used to flush the black tank. Backflow could be possible if the water supply was turned off while still connected to the black washout and another faucet on that same supply was opened elsewhere.The same reason anti-siphon valves are installed on sprinkler systems connected to a potable water supply.

Sorry, I now see what you are saying.:o

benagi 05-05-2017 12:32 AM

Black wash anti-siphon, anti-backflow valve ?
 
Does anyone know where the anti-siphon is for the 3171 or 3170? I looked under the vanity on saw some lines thru a hole to the left of the laundry hamper but couldn't see the anti-siphon valve. If anyone knows exactly where it is and could take a picture, I would greatly appreciate it.

Forester Fred 05-05-2017 08:08 AM

I don't have a 31XX series, I've got a 2301 - but - it took some doing for me to find mine. It's under the bathroom sink way up high. I had to lay on the floor and look up behind the sink with a flashlight to find it. It should be just inboard of the outside connection for the black tank flush.
http://www.forestriverforums.com/att...75dba4c158.jpg

I also replaced the plastic piece of garbage check valve with a brass one. Since I've done that - and cleaned the sawdust out of the nozzle that found it's way into the line during construction - my black flush system works perfectly.

http://media.wattswater.com/image/600/LF7R_1x75.psd.jpg

benagi 05-06-2017 12:12 AM

I like that brass valve. When I find my valve I will replace it with brass. Fred, where did you buy your new valve?

johnbryanpeters 05-06-2017 02:23 AM

There's a difference between a check valve and a backflow preventer.

Mr Havercamp 05-06-2017 02:55 AM

Quote:

Originally Posted by johnbryanpeters (Post 1496961)
There's a difference between a check valve and a backflow preventer.

Yes there is and the connector where the hose attaches outside, which is the same part used on your city water connection, is a check valve.

The cheap plastic backflow preventer in the line is an AVB (atmospheric vacuum breaker). If fluid tries to siphon back into the supply a small valve inside opens allowing air to enter the AVB which breaks the siphon. If that valve does not reseat when water pressure is applied, or if it leaks, then it ends up flooding your unit.

They install those only to be able to put that RVIA sticker on the rig as it's one of the requirements. I would just eliminate it and connect the line together. When you get right down to it, most water connections at campgrounds already have a backflow device right at the connection. The chances of the backflow police getting a warrant to inspect your rig are about 0.

johnbryanpeters 05-06-2017 03:15 AM

Quote:

Originally Posted by Mr Havercamp (Post 1496962)
Yes there is and the connector where the hose attaches outside, which is the same part used on your city water connection, is a check valve.

The cheap plastic backflow preventer in the line is an AVB (atmospheric vacuum breaker). If fluid tries to siphon back into the supply a small valve inside opens allowing air to enter the AVB which breaks the siphon. If that valve does not reseat when water pressure is applied, or if it leaks, then it ends up flooding your unit.

They install those only to be able to put that RVIA sticker on the rig as it's one of the requirements. I would just eliminate it and connect the line together. When you get right down to it, most water connections at campgrounds already have a backflow device right at the connection. The chances of the backflow police getting a warrant to inspect your rig are about 0.

They install these to avoid getting excrement in your water hose. I think I'll focus on keeping mine working.

Mr Havercamp 05-06-2017 03:42 AM

Quote:

Originally Posted by johnbryanpeters (Post 1496964)
They install these to avoid getting excrement in your water hose. I think I'll focus on keeping mine working.

Your choice, but not a good idea to use the same hose used for your potable connection at your tank flush?

Or just screw one of these to the flush connection then connect your hose.

http://m.homedepot.com/p/Everbilt-3-...Z4EB/205815672

Forester Fred 05-06-2017 06:51 AM

Quote:

Originally Posted by benagi (Post 1496956)
I like that brass valve. When I find my valve I will replace it with brass. Fred, where did you buy your new valve?

I don't remember exactly where. I couldn't find it in HD or Lowe's, checked with a couple local plumbing supply places, no luck. I ended up ordering online from a plumbing supply place. Google Watts LF7R and you'll get them to pop up. Watts lists it for preventing backflow. I pulled the plastic one out because it leaks...cheap piece of trash.

From Watts' website: Series LF7R Lead Free* Dual Check Valves prevent the reverse flow of polluted water from entering into the drinking water supply at the service entrance or at individual outlets. It consists of a Lead Free* cast copper silicon alloy body construction, with two compact replaceable plastic check modules, and stainless steel springs. Series LF7R is designed for non-health hazard residential water system containment, continuous pressure applications. It is installed immediately downstream of the residential water meter, in a vertical or horizontal position. Check with local inspection authorities for installation requirements. Minimum Working Pressure: 10psi (69 kPa) Maximum Working Pressure: 175psi (12 bar).

Forester Fred 05-06-2017 06:52 AM

Quote:

Originally Posted by Mr Havercamp (Post 1496968)
Your choice, but not a good idea to use the same hose used for your potable connection at your tank flush?

Or just screw one of these to the flush connection then connect your hose.

Everbilt 3/4 in. Hose Bibb Vacuum Breaker VACBFPZ4EB at The Home Depot - Mobile

Exactly - I have an older hose that I keep in my sewer compartment just for the black water flush. My "good" water hose is in another compartment so the two don't switched by accident.


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