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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.
  • My washer empties into black tank but you would know this as this is not a new motorhome so it is obviously equipment unless you have done something different. That flush was a likely culprit and maybe you will still determine it to be the problem while waiting a bit longer with it disconnected. Otherwise I will be interested in your final resolution of the mystery.
  • Black tank water sources.....
    *Toilet...water valve leaking thru and then toilet bowl seal would have to leak also
    *Flush system......water hose hooked up and water supply valve leaking thru (easy to check/cure----don;t hookup hose unless actually flushing tank
    *Bathroom sink.....some mfg. run sink drain to black tank. Excessive use adds lots of water (leaving water on while brushing teeth, combing hair, washing face/hands etc.) OR faucet leaking
  • Good thought, Down. I guess I thought that if the toilet were leaking, I'd hear it. We sat in there for several minutes, in complete silence, and heard nothing. And if it were flowing into the bowl, wouldn't I see it? It's dry.
  • Are you sure the blank tank is overflowing to the point it is back filling the toilet? Typically, that would not happen. I suspect that the toilet water valve is not completely shutting off, and thus a slight flow of water continues into the bowl until it overflows.

    To confirm my suspicion, pour a bottle of food coloring into the black tank. Allow it to fill and then let the toilet overflow. If you are right, the water in the toilet bowl will be colored by the food coloring. If I am right, the water in the overflowing toilet bowl will be clear.