Navien E740: Abnormal operation: outdoor temperature sensor
E740 is listed as 'Abnormal operation: outdoor temperature sensor.' for Navien Condensing Boiler. Verify the exact model and controller before acting.
Source checked 2026-05-01Error Codes
Browse published fault-code records by brand, product and displayed code.
Each record starts with the source meaning, then separates applicability, owner-safe actions, operating uncertainty and qualified-service boundaries. A matching code string alone is not enough: confirm the brand, product, model and controller before acting.
Navien E765: Abnormal external-pump
E765 is listed as 'Abnormal external-pump.' for Navien Condensing Boiler. Verify the exact model and controller before acting.
Source checked 2026-05-01Navien E774: Manual reset limit
E774 is listed as 'Manual reset limit.' for Navien Condensing Boiler. Verify the exact model and controller before acting.
Source checked 2026-05-01Navien E775: Auto reset limit
E775 is listed as 'Auto reset limit.' for Navien Condensing Boiler. Verify the exact model and controller before acting.
Source checked 2026-05-01Navien E777: Abnormal operation: LWCO limit (external device)
E777 is listed as 'Abnormal operation: LWCO limit (external device).' for Navien Condensing Boiler. Verify the exact model and controller before acting.
Source checked 2026-05-01Navien E782: Abnormal operation: boiler communication
E782 is listed as 'Abnormal operation: boiler communication.' for Navien Condensing Boiler. Verify the exact model and controller before acting.
Source checked 2026-05-01Navien E784: Abnormal operation: zone controller communication
E784 is listed as 'Abnormal operation: zone controller communication.' for Navien Condensing Boiler. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 118: Auto Switch from Electric to Diesel
Alarm 118 is listed as 'Auto Switch from Electric to Diesel' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 120: Check Alternator Excite Circuit
Alarm 120 is listed as 'Check Alternator Excite Circuit' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 121: Check PMW Liquid Injection Circuit
Alarm 121 is listed as 'Check PMW Liquid Injection Circuit' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 122: Check Diesel/Electric Circuit
Alarm 122 is listed as 'Check Diesel/Electric Circuit' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 123: Check Evap Coil Inlet Temp Sensor (CR)
Alarm 123 is listed as 'Check Evap Coil Inlet Temp Sensor (CR)' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 124: Check Evap Coil Outlet Temp Sensor (CR)
Alarm 124 is listed as 'Check Evap Coil Outlet Temp Sensor (CR)' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 125: Check Tank Level Sensor (CR)
Alarm 125 is listed as 'Check Tank Level Sensor (CR)' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 126: Check Back Pressure Regulator (CR)
Alarm 126 is listed as 'Check Back Pressure Regulator (CR)' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 127: Setpoint Not Entered (Zone)
Alarm 127 is listed as 'Setpoint Not Entered (Zone)' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 128: Engine Run Time Maint Reminder #1/Service Due
Alarm 128 is listed as 'Engine Run Time Maint Reminder #1/Service Due' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 129: Engine Run Time Maint Reminder #2
Alarm 129 is listed as 'Engine Run Time Maint Reminder #2' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 130: Engine Run Time Maint Reminder #1
Alarm 130 is listed as 'Engine Run Time Maint Reminder #1' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 131: Electric Run Time Maint Reminder #2
Alarm 131 is listed as 'Electric Run Time Maint Reminder #2' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 132: Total Unit Run Time Maint Reminder #1
Alarm 132 is listed as 'Total Unit Run Time Maint Reminder #1' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 133: Total Unit Run Time Maint Reminder #2
Alarm 133 is listed as 'Total Unit Run Time Maint Reminder #2' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 134: Controller Power On Hours
Alarm 134 is listed as 'Controller Power On Hours' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01Thermo King Alarm 135: Check Spare Digital Inputs
Alarm 135 is listed as 'Check Spare Digital Inputs' for Thermo King Truck/Trailer Refrigeration Unit. Verify the exact model and controller before acting.
Source checked 2026-05-01