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  #1  
Old 05-15-2021, 02:48 PM
rv3flier's Avatar
rv3flier rv3flier is offline
 
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Default Legacy RV-12 Fuel Tank Calibration

After having removed and reinstalled my fuel tank the calibration was lost. The builder recorded a table of mV values for calibration at 2 gallon intervals for a total of 9 readings reaching 14.8 gallons. Is there a way to re-enter these values into the Dynon 180 without having to drain and refill as was done originally?

Example: 1st reading empty: mV = 2731
2nd reading 2 gallons: mV = 2655
and so on to 9th reading 14.8 gallons: mV = 639
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  #2  
Old 05-15-2021, 07:20 PM
Mich48041 Mich48041 is offline
 
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Removing and reinstalling the fuel tank should not affect the calibration unless the float arm was bent.
Is the fuel level sender flange well grounded?
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  #3  
Old 05-16-2021, 02:34 AM
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[quote=rv3flier;1525858]Is there a way to re-enter these values into the Dynon 180 without having to drain and refill as was done originally?

Answer is no for D-180. I asked Dynon this question a couple of years ago.

So, why record the values? I don't know...
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  #4  
Old 05-16-2021, 06:51 AM
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Thanks for the feedback. I only disconnected and reconnected the wire from the sending unit. And, although I rotated the tank while out I was careful not to make any abrupt movements. So I doubt that the float arm was damaged in the process. However, since I have to drain and refill (thanks for the confirmation Jim) I'll soon find out if there's an issue with the sending unit.
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  #5  
Old 05-16-2021, 10:27 AM
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The ground connection that completes the circuit for the fuel level sensor is from the sensor flange to the fuel tank and then from the fuel tank to the air frame. If the removal and reinstallation of the fuel tank resulted in a slight electrical resistance between the tank and the airframe it would have an influence on the accuracy of the fuel level indication.
Use an ohm meter to check the resistance between the sensor flange and the air frame. If there is anything except for zero ohms that is your problem.
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  #6  
Old 05-18-2021, 07:51 AM
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Thanks for the suggestion Scott. I'm getting a ---- and "0" indication for fuel quantity, I'll check today.

The ground checked out OK. Finished draining the tank but it will be several days before I re-fill and calibrate.

Last edited by rv3flier : 05-18-2021 at 04:44 PM.
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  #7  
Old 05-18-2021, 08:24 AM
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Quote:
Originally Posted by rv3flier View Post
Thanks for the suggestion Scott. I'm getting a ---- and "0" indication for fuel quantity, I'll check today.
The nominal sensor resistance range is 30 ohms (full) and 240 ohms (empty), so any additional resistance caused by a poor ground path will make the indication read zero.
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  #8  
Old 05-20-2021, 05:08 PM
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rv3flier rv3flier is offline
 
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Well, there must be a break in the wire from the fuel sender and/or the float or arm became disconnected as the calibration readings didn't change with the addition of fuel. Since I have the Moeller fuel gauge as well, I'll wait until the next CI to deal with it.
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