Non-invasive Temperature-based Diagnostic Method

A Non-invasive Temperature-based Diagnostic (NTD) method for an Air Conditioning (AC) system in cooling mode, the method comprising:

• measuring AC system temperatures comprising a Return Drybulb Temperature (RDT), a Return Wetbulb Temperature (RWT), a Supply Drybulb Temperature (SDT), an Outdoor Air Temperature (OAT), a Suction Temperature (ST), and a refrigerant Liquid Temperature (LT);
• and
• entering the AC system temperatures into a processor memory and the processor performing processing steps comprising:
• monitoring the AC system temperatures reaching an equilibrium condition based on a rate of change of the AC system temperatures with respect to time;
• calculating an Actual Temperature Split (ATS) across an evaporator coil based on the RDT minus the SDT;
• determining a Required Temperature Split (RTS) based on the RWT and the RDT;
• calculating a Delta Temperature Split (DTS) based on the ATS minus the RTS;
• calculating a Liquid Over Ambient (LOA) temperature based on the LT minus the OAT;
• diagnosing proper Refrigerant Charge and Airflow (RCA) based on the DTS and the LOA or diagnosing at least one AC system fault based on the DTS, the OAT, the ST, and the LOA wherein the at least one AC system fault comprises a refrigerant undercharge with the processor estimating a refrigerant undercharge amount based on the DTS when the refrigerant undercharge fault is diagnosed;
• and
• reporting at least one message from the processor to a visual display or audible device, wherein the at least one message is selected from the group consisting of:
• the AC system has not reached the equilibrium condition for diagnostic testing,
• the proper RCA indicting the AC system is operating properly,
• the at least one AC system fault with information to enable repair of the at least one AC system fault, and
• the refrigerant undercharge fault and the refrigerant undercharge amount to add to the AC system to correct the refrigerant undercharge fault.

A Non-invasive Temperature-based Diagnostic (NTD) method for an Air Conditioning (AC) system in cooling mode, the method comprising:

• measuring AC system temperatures comprising a Return-air Drybulb Temperature (RDT), a Return-air Wetbulb Temperature (RWT), a Supply-air Drybulb Temperature (SDT), an Outdoor Air Temperature (OAT), a refrigerant Suction Temperature (ST), and a refrigerant Liquid Temperature (LT);
• and
• entering the AC system temperatures into a processor memory and the processor performing processing steps comprising:
• calculating an Actual Temperature Split (ATS) across an evaporator coil based on the RDT minus the SDT;
• determining a Required Temperature Split (RTS) based on the RWT and the RDT;
• calculating a Delta Temperature Split (DTS) based on the ATS minus the RTS;
• calculating a Liquid Over Ambient (LOA) temperature based on the LT minus the OAT;
• and
• diagnosing a proper Refrigerant Charge and Airflow (RCA) or diagnosing at least one AC system fault to subsequently correct based on at least one diagnostic wherein the at least one diagnostic for the proper RCA is based on the DTS and the LOA and the at least one diagnostic for the at least one AC system fault is based on the DTS, the ST, and the LOA when the at least one AC system fault is diagnosed;
• reporting at least one message to a visual display or an audible device wherein the at least one message is selected from the group consisting of:
• verifying the proper RCA indicting the AC system is operating properly, and
• reporting the at least one AC system fault with information to enable repair of the at least one AC system fault.