Patent ID: 9228757
Filing Date: 2016-01-05
CPC Classification: F24D,F24H

Claim Text:
1. A method for operating an air conditioning apparatus, said apparatus including a cabinet, an air blower including an electric blower motor for propelling air from an air inlet to an air outlet of said cabinet, and at least one electric heating element disposed in an air flowstream propelled by said blower through said cabinet, said apparatus further comprising a first temperature sensor for sensing the temperature of an enclosed space being supplied with conditioned air by said apparatus and a control system including a system controller operably connected to said first temperature sensor and to a second temperature sensor for sensing the temperature of air being discharged from said apparatus, said control system further including a heater interlock operable to prevent energization of said heating element and at least one heater relay in communication with said heater interlock, said method including the steps of: receiving by the system controller a status signal indicating the electric blower motor is operatively running above or below a maximum or a minimum speed, respectively; communicating by the system controller a shutoff signal instructing the heater interlock to prevent electrical power from being supplied to the at least one electrical heating element in response to the system controller receiving the status signal indicating the electric blower motor is operatively running above or below the maximum or the minimum speed, respectively; receiving by the system controller a status signal indicating at least one of (1) the air discharge temperature measured by the second temperature sensor exceeds a predetermined value and (2) a rate of change in the air discharge temperature measured by the second temperature sensor exceeds a predetermined value; and communicating by the system controller a shutoff signal instructing one of the heater interlock and the at least one heater relay to prevent electrical power from being supplied to the at least one electrical heating element in response to the system controller receiving the status signal indicating at least one of (1) the air discharge temperature exceeds the predetermined value and (2) the rate of change in the air discharge temperature exceeds the predetermined value.