Oil burners which have low fire start fuel control systems must deliver oil to the nozzle reduced pressure for low fire. This is normally accomplished by diverting a portion of the oil pump delivery through a by pass return line to the tank. The amount of oil delivered to the nozzle versus that returned to the tank is controlled by a device which limits or meters flow, thus an oil bypass regulating valve or an oil metering valve is used for this purpose.
1. Using screw driver, remove cover screw and gasket to gain access to the adjustment mechanism.
2. Use 1/8” Allen wrench to turn pressure adjusting screw clockwise to increase pressure and counterclockwise to decrease.
3. For initial start-up: Pressure at which oil will be delivered to the nozzle cannot be determined until the burner is test fired. Be prepared to adjust the regulator as the burner is cycled through its firing sequence.