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dshinnick's avatar
dshinnick
Explorer
Sep 03, 2016

Black tank overflow

Hey all-

We have a 2005 Holiday Rambler Ambassador, 40' DP. We're currently at a park on full hookups.

The wife heard dripping in the toilet room and found the bowl completely full of water and overrunning onto the floor. She yelled for me to turn off the water at the pole, which I did. I then opened the black tank valve, ran the sanicon, and drained the black tank. The water in the bowl went down and emptied normally. I continued running the sanicon til the black tank was empty.

Something is filling up the black tank without our permission. I flushed the toilet numerous times, every way I could, waited, and did not hear any signs that the toilet was running; no sounds of dripping into the tank. And when I fill the bowl with water, it holds for a reasonable length of time, like it's supposed to.

Out in the plumbing compartment I have a short run of hose connecting the built-in faucet to the black tank rinse input. Thinking that maybe that faucet was running and filling the tank, I disconnected the hose and waited, but nope; totally dry.

Remember that I had emptied the black tank right after the wife called me?

Well, after doing all the checking and troubleshooting I just described, I went out and ran the sanicon again, and there was a significant amount of water in the black tank. The sanicon ran for probably 15 seconds before running dry, so *something* put that water there since I'd emptied it 15 minutes before. I know I had put some in when troubleshooting the toilet, but it seemed like there was way more in there than I'd contributed.

So, bottom line: how can water get into the black tank other than the potty or the tank-cleaning-spray input?

I again emptied the black tank right before I came online, so I'll go back out right now and see how much accumulation there might be and I'll report.

dave

Just checked. It did drain some, but I accidentally left the gray valve open when I ran the sanicon, so some it may have been from the gray tank. I'll check again in awhile, and only open the black valve this time.
Class A
  • 1971duster340's avatar
    1971duster340
    Explorer
    Sep 04, 2016
    I didn't read all responses, but concerning your fresh tank unknowingly filling, do you normally fill the fresh water tank with the same hose hookup as your city water supply? Is there a valve that directs water to either fill your tank or thru the plumbing system? If so, the water pump on our MH was letting water backflow thru the check valve on the water pump when the fill valve was closed. I put another ball valve in the plumbing immediately after the pump and close it when we don't use tank water...The idea might need a one line drawing? This would have nothing to do with the blackwater issue.
  • -Gramps-'s avatar
    -Gramps-
    Explorer
    Sep 03, 2016
    You can find out if you have a one vent system just by looking for them on your roof. Mine is directly above the wet bay compartment.

    The funny thing is I am not sure if your toilet can fill the black tank and itself in a short time...if your foot pedal valve is not shutting off, it would fill the bowl, if the flush valve in the bowl is not closing and therefore leaking water into the tank the bowl is not going to fill up, well it might but it would take a long while if your coach is plumbed like mine. I suggest you drop a toilet packet in the bowl, let it dissolve which will add color to the bowl water and then see if it fades due to leaking into the tank.

    Oh, buy the way, I had a leak between the city water and the fresh water tank. I shut the water off and rapidly worked the lever a few times, the leak stopped. I suspect the ball value may have been stuck in a slightly open position and I exercised it loose.
  • dshinnick's avatar
    dshinnick
    Explorer
    Sep 03, 2016
    Gramps, we've been in this park for three days, and I always drain/flush the black tank when changing parks. After the toilet filled this morning I drained the black tank and it ran and ran. It sure seemed full. More full than I think we would have filled it with three days of normal use, especially when we always use the park's bathroom for #2's.

    And I have no idea if this coach has the one-vent system that you describe.
  • dshinnick's avatar
    dshinnick
    Explorer
    Sep 03, 2016
    I have a backflow preventer on the faucet connected to the black flush inlet, but yes, in theory, if that faucet were to seep, it would fill the black tank. The hose into the flush inlet is currently disconnected. I continue to hear water running, I'm assuming, into the fresh tank. I manually emptied the fresh tank down to 2/3, and am checking the monitor to see if/when it gets to full again, and then I'll monitor the black tank to see if anything changes in there.
  • -Gramps-'s avatar
    -Gramps-
    Explorer
    Sep 03, 2016
    Your toilet was full, but are you sure the black tank itself was the cause? It would have to have been very full to make the toliet overflow, it would have overflowed into the gray tank first and then out the shower and the water would have been brown. Some Monacos and HRs have one roof vent that connects to all the drains in your coach and water will back flow thru this connection from one tank to the other, I know that for a fact unfortunately.
  • dougrainer's avatar
    dougrainer
    Nomad
    Sep 03, 2016
    dshinnick wrote:
    So, it would seem we have two mysteries: why is the fresh water tank filling to overflowing with the valve in the City Water position, and why is the black tank filling to overflowing and backing up into the toilet?

    Anybody near Asheville, NC, want to come over and join in the fun?

    :0)


    1. The City Water valve is seeping and not shutting off for your water tank fill problem
    2. There are only 2 things going into the Black Tank. (1). The toilet. (2). The black flush. VERY FEW Motorhomes have the Washer or the Lavy Sink plumbed to the Black tank.
    3. As you found out and hopefully have disconnected, Having either a Y water hose connection or using the water Bay water faucet with a hose connected to the Black FLUSH input is NEVER a good idea. I advise customers that want to do that to install a minimum of 2 in line water valve shut offs to prevent a shut off from seeping and then filling the tank.
    4. IF you are positive the Toilet is not leaking water down and you have the Black water input hose connection NOT connected to anything, then I would suspect a previous owner has done some type of modification to the Flush piping. Some owners and I have done this for a flushing problem, have installed a fitting in the 3 inch down tube between the toilet and the top of the tank. connected to a valve by the toilet so when you flush the toilet, you open this valve only while flushing to help slide the debris into the tank. This modification is ONLY done when the down pipe has a few bends instead of a straight pipe into the top of the tank. Maybe a previous owner had this type system installed? Doug

    Forgot. NOT very common, but your water Pump valve could also seep. But that is easy to check. You remove the entry side water line when connected to City Water. You will know if it is leaking backwards.
  • Harvard's avatar
    Harvard
    Explorer
    Sep 03, 2016
    Try disconnecting the city water and use the water pump for a while. That would be one way of detecting running water by way of the water pump noise.
  • dshinnick's avatar
    dshinnick
    Explorer
    Sep 03, 2016
    So, it would seem we have two mysteries: why is the fresh water tank filling to overflowing with the valve in the City Water position, and why is the black tank filling to overflowing and backing up into the toilet?

    Anybody near Asheville, NC, want to come over and join in the fun?

    :0)
  • dshinnick's avatar
    dshinnick
    Explorer
    Sep 03, 2016
    Interestingly, I just noticed that my FRESH water tank overflow tube was dripping pretty substantially. I checked the inside monitor and the fresh tank shows full, which I'm pretty darned sure it wasn't when we arrived three days ago. Ok, we know there's a valve in the plumbing compartment which, when opened, directs fresh water into the fresh water tank. If that valve was leaking, allowing water into the fresh tank until it overflowed......how could THAT water get into the toilet and black tank?

    Aaaaargh!!!
  • dshinnick's avatar
    dshinnick
    Explorer
    Sep 03, 2016
    Yeah, me too, Golden.

    With my head stuck down into the plumbing compartment, I can hear water running. When I crimp the hose it stops or slow down drastically. When I release, it starts back up again. I shut off the valve to the toilet and I think there was no more draining into the black tank, but I'm going to wait a bit and check again.

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