Code ALARM 64: COMPRESSOR A1 THERMISTOR FAILURE
Issue Description & Safety Warning
The Carrier 48/50Z HVAC Rooftop PIC Alarm List has triggered a critical COMPRESSOR A1 THERMISTOR FAILURE alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
Code type: Alarm Source table: Table 73 Status Directory Displayed in: Status > Current Alarms Unit family: 48ZJ/ZL/ZW and 50ZJ/ZK/ZL/ZM/ZW/ZZ single-package rooftop units with Product Integrated Controls (PIC).
Source: Carrier 48/50Z-2T Controls Operation and Troubleshooting (Form 48/50Z-2T)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Carrier 48/50Z HVAC Rooftop PIC Alarm List Alarms
Carrier controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code ALARM 64 on the 48/50Z HVAC Rooftop PIC Alarm List identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Carrier's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 76 Carrier 48/50Z HVAC Rooftop PIC Alarm List codes.
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