System and method for controlling an HVAC unit based on thermostat signals

A method for controlling a heating, ventilating, and air conditioning (HVAC) unit, comprising:

• receiving a first thermostat input from a thermostat;
• setting a current mode of the HVAC unit to a heating mode when a heating signal is enabled in the first thermostat input, or to a cooling mode when a cooling signal is enabled in the first thermostat input;
• setting a current capacity percentage of the HVAC unit to a first capacity based on the first thermostat input;
• receiving an off indicator from the thermostat after setting the current mode of the HVAC unit;
• setting a current room temperature as a set point temperature for the HVAC to maintain in the current mode;
• waiting for a first timeout period for further signals from the thermostat;
• receiving only the off indicator from the thermostat during the first timeout period;
• setting the current capacity percentage of the HVAC unit to a minimum capacity in the current mode after receiving only the off value from the thermostat during the first timeout period;
• waiting for a second timeout period for further signals from the thermostat;
• receiving only the off indicator from the thermostat during the second timeout period;
• and
• turning off the HVAC unit after receiving only the off indicator from the thermostat during the second timeout period.

A non-transitory computer-readable medium comprising instructions for execution by a computer, the instructions including a computer-implemented method for providing a method for controlling a heating, ventilating, and air conditioning (HVAC) unit, the instructions for implementing:

• receiving a first thermostat input from a thermostat;
• setting a current mode of the HVAC unit to a heating mode when a heating signal is enabled in the first thermostat input, or to a cooling mode when a cooling signal is enabled in the first thermostat input;
• setting a current capacity percentage of the HVAC unit to a first capacity percentage based on the first thermostat input;
• calculating a first room heating/cooling change rate based on first temperature data received from the HVAC unit;
• comparing the first room heating/cooling change rate with a first threshold;
• maintaining the HVAC unit at the first capacity percentage if the first room heating/cooling change rate is equal to the first threshold;
• lowering the current capacity percentage by a first cooling increment, to a minimum of 0%, if the first room heating/cooling change rate is above the first threshold;
• raising the current capacity percentage by a second cooling increment, to a maximum of 100%, if the first room heating/cooling change rate is below the first threshold;
• receiving an off indicator from the thermostat after either maintaining the current capacity, lowering the current capacity, or raising the current capacity;
• setting a current room temperature as a set point temperature for the HVAC to maintain in the current mode;
• waiting for a first timeout period for further signals from the thermostat;
• receiving only the off indicator from the thermostat during the first timeout period;
• setting the HVAC unit to a minimum capacity percentage in the current mode;
• waiting for a second timeout period for further signals from the thermostat;
• receiving only the off indicator from the thermostat during the second timeout period;
• and
• turning off the HVAC unit.

A method for controlling a heating, ventilating, and air conditioning (HVAC) unit, which operates in a heating mode or a cooling mode with a current capacity based on temperature data from the HVAC unit, comprising:

• receiving a four-stage signal from a thermostat;
• determining whether the four-stage signal is a first stage cooling signal, a second stage cooling signal, a first stage heating signal, a second stage heating signal, or is off;
• when the four-stage signal is a first stage cooling signal
• calculating a first room heating/cooling change rate based on first temperature data;
• comparing the first room heating/cooling change rate with a first threshold;
• controlling a capacity percentage of the HVAC unit by lowering the current capacity by a first cooling increment, to a minimum of 0%, if the first room heating/cooling change rate is above the first threshold or by raising the current capacity by a second cooling increment, to a maximum of 100%, if the first room heating/cooling change rate is below the first threshold, and
• when the four-stage signal is a second stage cooling signal
• calculating the first room heating/cooling change rate based on first temperature data;
• comparing the first room heating/cooling change rate with a second threshold;
• controlling a capacity percentage of the HVAC unit by lowering the current capacity by a third cooling increment, to a minimum of 0%, if the first room heating/cooling change rate is above the second threshold or by raising the current capacity by a fourth cooling increment, to a maximum of 100%, if the first room heating/cooling change rate is below the second threshold,
• wherein
• the second threshold is different from the first threshold,
• the third cooling increment is different from the first cooling increment, and
• the fourth cooling increment is different from the second cooling increment.

A non-transitory computer-readable medium comprising instructions for execution by a computer, the instructions including a computer-implemented method for providing a method for controlling a heating, ventilating, and air conditioning (HVAC) unit, the instructions for implementing:

• receiving a four-stage signal from a thermostat;
• determining whether the four-stage signal is a first stage cooling signal, a second stage cooling signal, a first stage heating signal, a second stage heating signal, or is off;
• when the four-stage signal is a first stage cooling signal
• calculating a first room heating/cooling change rate based on first temperature data;
• comparing the first room heating/cooling change rate with a first threshold;
• controlling a capacity percentage of the HVAC unit by lowering the current capacity by a first cooling increment, to a minimum of 0%, if the first room heating/cooling change rate is above the first threshold or by raising the current capacity by a second cooling increment, to a maximum of 100%, if the first room heating/cooling change rate is below the first threshold;
• and
• when the four-stage signal is a second stage cooling signal
• calculating the first room heating/cooling change rate based on first temperature data;
• comparing the first room heating/cooling change rate with a second threshold;
• controlling a capacity percentage of the HVAC unit by lowering the current capacity by a third cooling increment, to a minimum of 0%, if the first room heating/cooling change rate is above the second threshold or by raising the current capacity by a fourth cooling increment, to a maximum of 100%, if the first room heating/cooling change rate is below the second threshold,
• wherein
• the second threshold is different from the first threshold,
• the third cooling increment is different from the first cooling increment, and
• the fourth cooling increment is different from the second cooling increment.