60 u00b0 f and 29 92 u2033 hg based on the known fuel input the burner requires 10 000 pounds per hour of air to completely and efficiently burner all of the fuel provided by the burner the following analysis would be used to generate the control strategy the densities of the air at the two conditions are from eqn 1 lb air hr pounds of air required per hour as stated in this example standard air density 0 0765 lb ft 3 standard air pressure 29 92 u2033 hg local air pressure 28 7 u2033 hg air temperature at condition 1 120 u00b0 f air temperature at condition 2 50 u00b0 f and rpm revolutions per minute the burner was setup under condition 1 at 120 u00b0 f which is the lowest air density the combustion air motor and fan are operating at 3500 rpm and the air damper is adjusted to generate a flow of 2533 cfm which provided enough air to completely burn the fuel and some minimal amount of excess air for good combustion efficiency at condition 2 the fan will generate the same volume of air based on fan laws and since the density is much higher more pounds of air per volume at this lower air temperature the burner would normally have much more air then needed for combustion a higher excess air rate would result in lower combustion efficiency the system of the present invention will change the fan speed to match the changes in air temperature and provide the same mass of air to the burner firing head 30 the new fan speed.