Author Topic: Black tank capacity?  (Read 2172 times)

Lonne Mays

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Black tank capacity?
« on: December 06, 2019, 02:09:56 AM »
My 1999 Contessa owner's manuals state that the black tank capacity is 40 gallons and that the grey is 80 gallons.  From the attached picture it is easy to observe that the black and grey tanks are the same size, and both appear to be about the physical size (in cubic feet) to be 80 gallon tanks.  Is the capacity of the black tank only 40 gallons because it it never supposed to be filled up more than half way?  Or is the capacity stated in the owner's manual wrong?

Steve Huber Co-Admin

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Re: Black tank capacity?
« Reply #1 on: December 06, 2019, 03:15:54 AM »
Lonne,
The right hand tank looks relatively new.
Steve
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Fred Brooks

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Re: Black tank capacity?
« Reply #2 on: December 06, 2019, 01:26:15 PM »
     Lonne, You can measure the tank, length X height X width equals total square inches. Then divide by 231 will give you "gross gallons" The tank has built in draft, so measure each end and then average the difference. Example 60 X 20 X 10=12,000 divided by 231 equals 51.94 gross gallons. Subtract 10% for tank thickness and air space equals 46.75 approximate capacity. Fred
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Mike Shumack

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Re: Black tank capacity?
« Reply #3 on: December 06, 2019, 01:57:32 PM »
Having a larger Grey tank (than the Blank tank) would be smart - but seems every Coach I've seen has the same size tanks.

And the 1999 Contessa specs says they are the same size. So one of the publications has a typo. I think the typo is in your manual. You could get a five gallon bucket and dump buckets of fresh water in the tanks (when empty) and see when they read "full". Dump it in Shower drain to check grey tank.