When reading inches on the display you can disregard the digits after the decimal points. The amount of fuel indicated by increments smaller than one inch is always less than 59 gallons. And since the estimated accuracy of the transmitter is plus-or-minus one-half inch, increments smaller than one inch are not always reliable.

Incidently, on earlier tanks that have transmitters set to display feet, you should consider the digits after the decimal point. The amount of fuel indicated by increments smaller than one foot could range up to 700 gallons, which is a significant amount.

SPECIFIC GRAVITY
Specific gravity is the weight of fuel compared to an equal volume of water at the same temperature. Pure water weighs 8.333 pounds per gallon and has a specific gravity of 1.000. Thus, the specific gravity of fuel equals the weight of fuel divided by the weight of water. If you don’t know the specific gravity of the fuel you use, ask your supplier.

Heatec normally sets the transmitter for a specific gravity of 0.880 before the tank is shipped. This is the specific gravity of waste oil. Other fuel oils have somewhat different specific gravities.

Figure 3. Specific Gravities Of Fuels and Transmitter Settings
Commercial fuels	Specific Gravity at 60 degrees F	Transmitter Full Scale Blind Settings (Mode 6)
	0.970	566.5
No. 6 oil	0.965	563.6
	0.960	560.6
	0.955	557.7
	0.950	554.8
No. 5 oil	0.945	551.9
	0.940	549.0
	0.935	546.0
	0.930	543.1
	0.925	540.2
	0.920	537.3
	0.915	534.4
	0.910	531.4
	0.905	528.5
No. 4 oil	0.900	525.6
	0.895	522.7
	0.890	519.8
	0.885	516.8
Waste oil	0.880	513.9
	0.875	511.0
	0.870	508.1
	0.865	505.2
	0.860	502.2
	0.855	499.3
No. 2 oil	0.850	496.4
	0.845	493.5
	0.840	490.6
	0.835	487.6
	0.830	484.7
The full scale blind setting is equal to a tank height of 600 inches minus the sensor height of 16 inches multiplied by the specific gravity of the fuel.