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Danny ONeill · 08-17-2019, 01:54 PM

This is an odd one; in our 1995 Classic 36’ diesel pusher, the water pump will cycle on about every 7 minutes...and somehow the water seems to be going into the black tank? I even shut the water off to the stool, thinking that I’d isolate the leak, but not so? Any ideas where to look? Even if it’s leaking into the gray tank...how would it get there and where do I look? Thank you very much!

mayco · 08-17-2019, 02:38 PM

How long is it "on" when it cycles? It must be dumping a good deal of water into the tank for it to be detectable. There is only one way that I know of to put water, or anything else, into the black tank and that's the toilet flushing. Unless it's from the outside dump valve I suppose. When you put water in the toilet bowl does it stay or leak past the slider into the tank? It's possible for the toilet valve to leak into the bowl I guess, but you said you tried turning that off.......that's a good mystery you have going there.

Now if you're not absolutely sure where the water is going when it cycles then that's a different story. That could be the check valve in your water pump has gone bad and dropping your water pressure in your pipes.

Danny ONeill · 08-17-2019, 04:48 PM

It cycles about every 7 minutes and 45 seconds...within 5 seconds. Super consistent. I drained both tanks today so will run another little experiment overnight; shouldn’t be a drop in black tank tomorrow.

Check valve sounds super logical...I’ll look at it, too.

I very much appreciate your help, thank you. I have a new conundrum that I’ll post here as well.

J. Morgan · 08-17-2019, 04:55 PM

If there's no visible leakage, chances are the check valve in the pump has a little murmur, and the water isn't going anywhere except a tiny slow backwash to the freshwater tank.

Danny ONeill · 08-17-2019, 05:27 PM

Quote:

Originally Posted by J. Morgan

If there's no visible leakage, chances are the check valve in the pump has a little murmur, and the water isn't going anywhere except a tiny slow backwash to the freshwater tank.

[emoji1360]. Thank you very much.[emoji119]