2018 Bighorn 3870

Our camper has a bath and a half also two separate black water tanks.
There appears to be what I believe is to connections for black tank wash outs one for each tank.
When I connect a hose to one of them water squirts out of the other one and does not go to the black tank.
Suggestions anyone..

Thanks
see photo

If you're sure that when connected to one of the flush connectors, water sprays out the other, it would suggest they're cross connected. To confirm that, take down the rear wall of the basement pass through storage, behind the UDC so you can see how the lines are connected.

danemayer said:

If you're sure that when connected to one of the flush connectors, water sprays out the other, it would suggest they're cross connected. To confirm that, take down the rear wall of the basement pass through storage, behind the UDC so you can see how the lines are connected.

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I took the rear wall out to check the back of the panel both intakes were attached to sections of a water hose that went down into the bottom of the camper and I could not see where they attached.


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Michael47 said:

I took the rear wall out to check the back of the panel both intakes were attached to sections of a water hose that went down into the bottom of the camper and I could not see where they attached.


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Attached to different hoses, or attached to the same one?

danemayer said:

Attached to different hoses, or attached to the same one?

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Two different hoses.

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Ok, my working theory is that the hoses got cross connected and both flush inlets are tied to the same Anti-Siphon Valve.

If both inlets are connected to the same anti-siphon valve, water will flow in one direction only, so a water connection to one inlet will spurt water through the other inlet. Connection to the other inlet will do nothing.

Here's a test.

1. Empty both black tanks
2. Leave both gate valves open
3. Attach a water hose to one of the flush inlets.
4. Turn the water on.
5. See if any water comes out the other flush inlet.
6. Also see if any water comes out of the sewer outlet.

If water only comes out of the other flush inlet, and no water comes out of the sewer outlet, I think that would argue that both hoses from the inlets are connected to one anti-siphon valve.

If no water comes out of the other flush inlet, and no water comes out of the sewer outlet, move the water to the other flush inlet and try again.

If water now comes out the other flush inlet and nothing from the sewer outlet, that would again argue that both hoses are connected to one of the anti-siphon valves.

If water going into either flush inlet produces a stream of water coming out of the sewer outlet, something else is wrong.

Michael, did you find a solution to flushing out the two black water tanks?

this is the same issue we are having. Michael did you find a solution or is it best to contact Heartland?

I agree with Dan - sounds like the lines were cross connected at the vacuum breaker. Though messy, here's what I would do:

1. Expose the 2 vacuum breakers
2. Wrap a towel around the lines below them
3. Remove the vacuum breakers
4. With the shore water hose connected to one of the black tank rinse inputs in the UDC, have an assistant turn on the water a tiny bit
5. Note which line water comes out of and mark it
6. Swap the shore water hose to the other black tank rinse input in the UDC and repeat steps 4 and 5
7. Connect one of the input lines at the vacuum breaker to the input of one vacuum breaker and connect one of the outputs to the output of the same vacuum breaker
8. Connect the shore water hose to the black tank rinse input in the UDC for the vacuum breaker input line you connected
9. Have the assistant turn the water on a tiny bit while you observe at the vacuum breakers. If there is no leak, turn the water on 100%. If still no leaks water should be getting into one of your tanks
10. Repeat steps 6 through 9

ba5online said:

I have this same problem. I own a 2018 Big Country 3950FB (bath and a half) with 2 gray tanks and and a black tank with 2 flush ports.
So, if both flush out lines are "Yed" together, then would reversing the input/output to back flow preventer cure this or would one flush
port still backflow to the other flush port? Are there any plumbing diagrams that actually show how flush out lines are connected in a Heartland 3 tank system?
How many backflow preventers should a 3 tank system have? Thanks,

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I've never seen or heard of 2 black tank flush lines be connected to each other by design.

I too have a bath and a half model. Two flush ports. Each port goes to it's own vacuum breaker. Those vacuum breakers are located in the same spot.

The output of each vacuum breaker goes to its corresponding black tank.

Haven't heard of a Heartland coach with 3 black tanks (though there could be some). In these cases, I'd assume there's a 3rd black tank flush port mounted somewhere.

In my half bath, they are in the upper bathroom shower wall (on the end that the shower valve/head are on).

Looking at your floor plan, my guess is that yours are in the same place. Look for an access to them below the shower valve behind a removable round access panel. Careful of the long screws used for the panel trim - you'll scrape yourself good.

ba5online said:

Where are your 2 backflow preventers located, in the front bathroom under sink? For the 2 grey tanks,
first the flush water goes thru the backflow preventer and then "Y"d off to each grey tank? Thanks,

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To confirm: The gray tanks do not have a flush/rinse sprayer in them. Water path is:
Black Tank Flush Water Connector (usually in UDC) > Atmospheric Vacuum Breaker (up high in an interior wall) > Sprayer in Side Wall of Black Tank

I don’t understand how they would have a single ASV serve two tank flush systems. Joining the lines with a simple wye is not going to do it. You need to get in there and get eyes on how they did it. Pressure in one input line will back feed out the other. On the output side of the ASV a wye is not going to select one system over the other.


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ba5online said:

Jim, did you have this same trouble as I of water coming out the 2nd flush port?

Did you reverse the connections at the anti-siphon valve(s) using a PEX tool or where these connected with hose fittings?

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No. Mine we're plumbed right.