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Old 07-12-2019, 05:14 PM   #1
Getn off
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Join Date: Sep 2018
Location: Micky Town
Posts: 91
Black AND gray tanks wont dump!

Hello all.
In the middle of a 2 week trip from Orlando, Savannah, Gatlinburg, Oconee NF, Savannah, Orlando. All going fairly well so far.
Stayed in Oconee NF for the last 5 nigts. No dump at site, just at exit. No problem, as we have 2 large gray and 1 large black tank. Went to leave this morning and stopped by the exit to dump. Rear gray dumped fine. Forward gray and black no joy. Nothing at all! Handles seemed to move normally. Tried cycling handles in and out many times. Again, all felt normal. Even tried flushing a bit the black tank. Didnt do much because it indicated full. Gray indicated 1/2 btw.
I even tried tapping the line above and below the barrier. Nothing. A line was growing behind me so I had to go.
Called Keystone tech and although they were very courteous, they were zero help. Just told me it didnt make sense as it sounded like both forward valve nuts may have came loose at the same time?!
I was hoping that movement on the road would jar something free. As luck would have it, it did! When I got to Savannah, I tried to dump and it worked perfect! Handles feel the same still.
Anyone know how these things are plumbed? I assume valves for each are seperTe after the tanks, then into a Y to a single outlet outside. But nothing makes sense as to why it would get stuck together. If it was sediment lodged in the black tank tube, why would the gray not work? Maybe a clog after the black valve??? Which makes zero sense to me.
It worked perfect 6 days before. I drained black, flushed 3 times till clear, then gray tanks.
Wondering if I need to take this in, or just chalk it up as a clog??
Anyone experience this?
2018 Keystone Sprinter Limited 3551fwmls
Thanks for any help.

2018 Keystone Limited 3551FWMLS.
2018 F350 CC Powerstroke dually with 4.10s.
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Old 07-12-2019, 05:45 PM   #2
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Join Date: Jul 2014
Location: Modesto
Posts: 9,214
I would watch it. If it happens again then think about a service appointment. Valves will usually be right at the tank outlet and if you have two next to each other then they are joined at some point along the way.


2012 Copper Canyon 273FWRET being towed by a 1994 Ford F350 CC,LB,Dually diesel.
Airlift 5000 bags, Prodigy brake control, 5 gauges on the pillar.Used to tow a '97 Jayco 323RKS.

Now an RVIA registered tech. Retired from Law enforcement in 2008 after 25+ yrs.
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Old 07-13-2019, 02:53 AM   #3
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Join Date: Oct 2017
Location: Brisbane Australia
Posts: 475
Another possibility that I read on the forums here. When the hole is drilled in the bottom of the tank, what happens to the piece that is cut out? If it gets left in the tank, it could cover the drain hole. That would explain why it worked after traveling a bit. The piece moved away from the drain hole.
If that's the case, then the question becomes, how to get that out of the tank?
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Old 07-13-2019, 06:43 PM   #4
Getn off
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Location: Micky Town
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I will def keep an eye on it for sure.
Hope it isnt a lag, but just some strange clog.
2018 Keystone Limited 3551FWMLS.
2018 F350 CC Powerstroke dually with 4.10s.
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