ATF: Gateway - Black Tank Flush System - 2015 GW 3750 PT

I attempted to use the black tank flush system today but encountered an issue. I hooked up my hose to the connector, open the dump valves (drained tanks prior) and left them open, then turned on the water to flush the tanks. Well water spurted out from the connection. I thought maybe it was the pressure but I tried running it with the water barely on and with the regulator... same results. Water was coming out the sewer hose but very little. All connections were tight was well. I used a 15ft garden hose from Lowes. Does it have to be a RV/Marine hose?
 

Bones

Well-known member
I attempted to use the black tank flush system today but encountered an issue. I hooked up my hose to the connector, open the dump valves (drained tanks prior) and left them open, then turned on the water to flush the tanks. Well water spurted out from the connection. I thought maybe it was the pressure but I tried running it with the water barely on and with the regulator... same results. Water was coming out the sewer hose but very little. All connections were tight was well. I used a 15ft garden hose from Lowes. Does it have to be a RV/Marine hose?
I had a very similar problem and it turned out to be my anti siphon valve had turned. I took out the drawers in the kitchen and set the valve upright and zipp-tied it up and tapped it a few times and it has worked since.
 

GWRam

Well-known member
Bones,
Where behind the kitchen drawer is the valve? Is it along the outside wall or further into the camper? And how far up?
Thanks
Dave


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Bones

Well-known member
I just looked up your Model and your kitchen is a little different. Is the clean-out for the rear tank on the door side of the RV? Mine is right around the rear bathroom. almost eye level
 

GWRam

Well-known member
Our black flush external hose connection is on door side, eye level just forward of rear bathroom door. Sound like the out side portion is the same or similar.


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Bones

Well-known member
Our black flush external hose connection is on door side, eye level just forward of rear bathroom door. Sound like the out side portion is the same or similar.


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Here are two pictures. Both show my black tank hook up. if yours is the same you need to figure out where that comes through on the other side. My came through and was sitting right behind my set of drawers. Yours doesn't have drawers but an oven on that side. You may have to take the knife holder tray behind the oven off to see the anti siphon device. You could also see if you can remove the drawer under the oven and look behind there to see the lines. This is all granted that your connection is in the same location as mine.

0414161105.jpg0412160944.jpg
 

GWRam

Well-known member
Thank You for the photos, as far as the Black Tank Flush connections our units are the same. I will do some digging around to find where our line runs.
Its interesting to see your 2015 and note the differences one year makes. Our unit has the furnace below the BTF connection and the bathroom door only
opens 90* on a strut.
Thanks again.
 

Bones

Well-known member
Thank You for the photos, as far as the Black Tank Flush connections our units are the same. I will do some digging around to find where our line runs.
Its interesting to see your 2015 and note the differences one year makes. Our unit has the furnace below the BTF connection and the bathroom door only
opens 90* on a strut.
Thanks again.
GWRam, I am getting myself confused. You have the same unit so stand in your kitchen facing the sink and the drawers to your left are where the line is. Pull those drawers out. and the line should be there in the back. Our heater is under that little useless sofa chair as you walk in the main door.

- - - Updated - - -

0423161106.jpg

Here are the drawers. You can see the blue line on the left in the picture.
 

GWRam

Well-known member
Bones,
I didn't mean to cause confusion, and thanks for the photos. I was just glad to read the info you posted and jumped in asking questions.

Stompatron,
I didn't mean to hijack your thread. To answer your questions, any hose will do. I have a separate hose that I use only for the purpose of black tank flushing and connecting to the water supply at dump stations.
As far as the water not going into your black tank flush connector. Make sure that the one way check valve at the hose connection on the side of the camper isn't installed backwards. If it is. I should wiggle loose
and can be pulled out and then reversed and put back in place. The water spraying out around the connection just sounds like a loose connection and or bad washer seal.

Dave
 

danemayer

Well-known member
I can't find the post, but I think someone recently had a similar problem where water would not go through the black tank flush system and into the tank. If I remember correctly, he found the line kinked in the underbelly on it's way to the black tank.
 
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