RPM control method of blower for gas furnace

A method of controlling an RPM of a blower for a gas furnace that passes air to be supplied to a room around a heat exchanger of the gas furnace, the method comprising:

• starting operation of the gas furnace;
• measuring an air temperature at an outlet side of the gas furnace;
• measuring the RPM of the blower;
• determining whether the air temperature falls within a reference temperature range having a lower limit temperature and an upper limit temperature, or whether the air temperature is lower than the lower limit temperature of the reference temperature range,
• in response to the determination that the air temperature is lower than the lower limit temperature and based on a determination that the blower is not operating, transmitting a first control signal to the blower and thereby maintaining an inoperative state of the blower,
• in response to the determination that the air temperature is lower than the lower limit temperature and based on a determination that the blower is operating, transmitting a second control signal to the blower and thereby reducing a current RPM of the blower by a certain amount, and
• in response to the determination that the air temperature falls within the reference temperature range having the lower limit temperature and the upper limit temperature, transmitting a third control signal to the blower and thereby maintaining a current RPM of the blower.