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Old 03-14-2015, 08:41 PM   #1
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Woodyacme's Avatar
1996 30' Land Yacht
Flagler Beach , Florida
Join Date: Dec 2014
Posts: 25
Question about tanks and "dummy lights"

Last night, we "dumped" the grey and black water tanks from what was in there when I bought the coach.

Couple of questions:

1. Using the "test" button above the stove, it is labeled Holding tank 1 and holding tank 2, question is which one is the black water and which one is the grey water?

2. When you connect a hose to the inlet down in front of the grey water valve, and put water into the tank(s) which tank does that go into? My guess is that it goes into the black tank so that you can flush any remaining solids?

My test indicator says that holding tank 1 is 2/3 full and holding tank 2 is 1/3 full. I was connected to the sewer for almost 10 hours last night at the campground that we stayed at. I left the grey valve open and the black one closed, (heard that on youtube) to fully drain the tanks, but tank 1 is still almost full. After opening the black valve and waiting for the sound to stop, I then re-opened the grey valve to flush. Waited for the sounds to stop then closed that valve, however the lights inside still don't show empty...

Does not really matter what the "dummy lights" say, I just want to prevent a back-up, so I am going to assume (for the sake of this conversation) that the lights are accurate.

Going to connect to the sewer tomorrow after I fix a small leak in the sewer hose & change to a clear end so I can see when the fresh water is flushing thru the hose.

Thanks for any assistance.

Steve Woodin
1996 30' Land Yacht
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Old 03-16-2015, 07:37 PM   #2
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Skater's Avatar
1995 30' Excella
Bowie , Maryland
Join Date: Apr 2005
Posts: 2,344
The tank sensors often aren't accurate. Ours shows our blank tank as 2/3rds full all the time. Stuff dries on the sensors and they stop working correctly. You can buy liquid cleaner or use a high pressure sprayer to try to clean them.

1995 Airstream Classic 30' Excella 1000
2014 Ram 2500 Crew Cab with Cummins 6.7L Diesel

Sold but not forgotten: 1991 Airstream B190
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Old 03-17-2015, 01:22 PM   #3
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2010 30' Classic
Vintage Kin Owner
South of the river , Minnesota
Join Date: Dec 2009
Posts: 4,133
Typically 1 = main = black
2 = aux = gray

As Skater points out, holding tank sensors of all kinds and eras are notoriously unreliable. Black tank you can just hold the flush pedal down and use a flashlight to look in and see how deep it is. Grey tank who knows
To learn to see below the surface, you must adjust your altitude
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Old 04-20-2015, 09:34 AM   #4
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Alden Miller's Avatar
1993 34' Excella
, Maryland
Join Date: Jun 2005
Posts: 223
Images: 2
Originally Posted by Skater View Post
The tank sensors often aren't accurate. Ours shows our blank tank as 2/3rds full all the time. Stuff dries on the sensors and they stop working correctly. You can buy liquid cleaner or use a high pressure sprayer to try to clean them.
My black water tank shows partially full even just after being emptied. The tank is pretty clean, I have done the detergent, ridex, and ice cube cleaning on it. Where would the sensors be in the tank so I can see if they are gunked up?

1993 34' Excella 1000
2005 Dodge Ram 3500 Diesel
(No it doesn't have a HEMI in it)
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