Outdoor Thermistors Fault
Mitsubishi · MSZ-FH06-18NA Heat Pump System
What does 6-time blink 2.5-second OFF mean?
This fault occurs when any outdoor thermistor (e.g., ambient, discharge, liquid line) experiences a short or open circuit during compressor operation. This prevents the outdoor unit from accurately sensing temperatures, impacting defrost cycles, capacity control, and overall system efficiency. Failure to address this can lead to system instability, freezing, or inefficient heating/cooling.
Complete Troubleshooting Guide
- 1
Consult the outdoor unit service manual's 'Check of outdoor thermistor' section for specific resistance values at various temperatures.
- 2
Using a multimeter, measure the resistance of each outdoor thermistor and compare these readings against the specified characteristics.
- 3
Carefully inspect all thermistor wiring and connectors for secure connections, signs of corrosion, or physical damage.
- 4
Identify and replace any outdoor thermistor that tests faulty or shows signs of damage.