Stepper motor gas valve and method of control

A controller for a variable heating system having a variable rate gas valve configured to adjust a gas flow rate to vary the level of heating operation, the controller comprising:

• a first terminal configured to receive a thermostat signal requesting heating operation;
• an electronic memory;
• and
• a microprocessor in communication with the electronic memory and the first terminal, the microprocessor being configured to detect the presence of a thermostat signal requesting heating at the first terminal and to generate a control signal for the variable rate gas valve to operate the variable rate gas valve for establishing heating operation, the microprocessor including a programmable read-only-memory encoded with an instruction to store in the electronic memory a time duration during which the microprocessor detects the presence of a thermostat signal requesting heating, and further encoded with an instruction operable to determine a predetermined heating level based on the stored time duration, wherein the microprocessor is configured to respond to the detection of a thermostat signal requesting heating by determining the predetermined heating level, and generating a gas valve control signal corresponding to the predetermined heating level that is applied to the variable rate gas valve to adjust the variable rate gas valve to the gas flow rate corresponding to the predetermined heating level;
• wherein the instruction is configured to determine a new predetermined heating level by decrementing the heating capacity level of the last heating cycle by a predetermined percentage for each minute the stored time duration of the signal requesting heating is less than a threshold time period.

A controller for a variable heating system having a variable rate gas valve configured to adjust a gas flow rate to vary the level of heating operation, the controller comprising:

• a first terminal configured to receive a thermostat signal requesting heating operation;
• an electronic memory;
• and
• a microprocessor in communication with the electronic memory and the first terminal, the microprocessor being configured to detect the presence of a thermostat signal requesting heating at the first terminal and to generate a control signal for the variable rate gas valve to operate the variable rate gas valve for establishing heating operation, the microprocessor including a programmable read-only-memory encoded with an instruction to store in the electronic memory a time duration during which the microprocessor detects the presence of a thermostat signal requesting heating, and further encoded with an instruction operable to determine a predetermined heating level based on the stored time duration, wherein the microprocessor is configured to respond to the detection of a thermostat signal requesting heating by determining the predetermined heating level, and generating a gas valve control signal corresponding to the predetermined heating level that is applied to the variable rate gas valve to adiust the variable rate gas valve to the gas flow rate corresponding to the predetermined heating level;
• wherein the instruction is configured to determine a new predetermined heating level by incrementing the heating capacity level of the last heating cycle by a predetermined percentage for each minute the stored time duration of the signal requesting heating exceeds a threshold time period.

A controller for a variable heating system having a variable rate gas valve configured to adjust a gas flow rate to vary the level of heating operation, the controller comprising:

• a first terminal configured to receive a thermostat signal requesting heating operation;
• an electronic memory;
• and
• a microprocessor in communication with the electronic memory and the first terminal, the microprocessor being configured to detect the presence of a thermostat signal requesting heating at the first terminal and to generate a control signal for the variable rate gas valve to operate the variable rate gas valve for establishing heating operation, the microprocessor including a programmable read-only-memory encoded with an instruction to store in the electronic memory a time duration during which the microprocessor detects the presence of a thermostat signal requesting heating, and further encoded with an instruction operable to determine a predetermined heating level based on the stored time duration, by decrementing the heating capacity level of the last heating cycle by a predetermined percentage for each minute that the stored time duration is less than a threshold time period, or by incrementing the heating capacity level of the last heating cycle by a predetermined percentage for each minute that the stored time duration exceeds a threshold time period, wherein the microprocessor is configured to respond to the detection of a thermostat signal requesting heating by determining the predetermined heating level, and generating a gas valve control signal corresponding to the predetermined heating level that is applied to the variable rate gas valve to adjust the variable rate gas valve to the gas flow rate corresponding to the predetermined heating level.