Abstract: A method is described for distinguishing non-condensables from refrigerant over-charge, and refrigerant restrictions from refrigerant under-charge of a cooling system and calculating an amount of refrigerant to be added or removed to the cooling system for optimal performance. Expanded target temperature split and target superheat tables and delta superheat tolerances are provided based on laboratory data and mathematical algorithms. The methods may apply to Fixed Expansion Valve (FXV) and Thermostatic Expansion Valve (TXV) systems and may include making and displaying a diagnostic recommendation regarding non-condensables, refrigerant restrictions, or refrigerant adjustment based upon measurements of return-air wetbulb and drybulb temperatures, condenser entering air temperature, refrigerant suction line temperature, refrigerant liquid line temperature, refrigerant vapor and liquid line pressures, and refrigerant superheat and subcooling temperatures.

Abstract: A method for efficient control of a heater ventilation fan. The method includes switching the heater ventilation fan from low speed to high speed after a brief period P1 following starting, and continuing heater ventilation fan operation for a variable period of time P2 after the heat source has stopped. The period P1 is preferably about four minutes, and the period P2 is determined by the duration of heating and is generally between two and four minutes. Operating the heater ventilation fan at high speed improves heat transfer and efficiency while the heating system is operating, increases warm air movement to the space, satisfies the thermostat set point temperature in less time, reduces heating system operation, and reduces energy use. Continuing heater ventilation fan operation after turn-off maximizes recovery of additional heat from the heat exchanger to improve overall efficiency, extend the off cycle time, and save energy.

Abstract: Expanded temperature split, superheat, enthalpy, humidity, and wet-bulb tables are created and used to determine recommended refrigerant charge and airflow adjustments. Previously unknown enthalpy split values are introduced and calculated in a defined region and then extrapolated using a nonlinear curve fit for undefined regions. Undefined target temperature split values are then calculated from a relationship between temperature split and enthalpy split. Previously undefined superheat values are extrapolated using a nonlinear curve fit from a defined region to obtain superheat values for undefined regions. The expanded temperature split and superheat tables are used during setup or maintenance to calculate refrigerant and/or airflow adjustments for optimal performance of the cooling system in previously undefined operating regions.

Abstract: Expanded temperature split, superheat, enthalpy, humidity, and wet-bulb tables are created and used to determine recommended refrigerant charge and airflow adjustments. Previously unknown enthalpy split values are introduced and calculated in a defined region and then extrapolated using a nonlinear curve fit for undefined regions. Undefined target temperature split values are then calculated from a relationship between temperature split and enthalpy split. Previously undefined superheat values are extrapolated using a nonlinear curve fit from a defined region to obtain superheat values for undefined regions. The expanded temperature split and superheat tables are used during setup or maintenance to calculate refrigerant and/or airflow adjustments for optimal performance of the cooling system in previously undefined operating regions.