Testing the Thermistors

Testing the Thermistors

Remember!!

Thermistor Fault

All Mitsubishi VRF thermistors are NTC (Negative Temperature Coefficient) sensors

5106

When a thermistor faults the system will tell you which specific thermistor has failed in the fault code The thermistor faults always start with 51 then the next two digits indicate which thermistor number has faulted For examle: If TH6 failed the fault code would be

Use a standard multi meter on the Ohms setting to test the resistance value of the thermistors

When a thermistor fault occurs you can use the SW4 dip switches to read the temperature value being reported back to the PCB You should always test the resistance value of the suspected faulty thermistor to make sure the PCB is not reading the values of the thermistor incorrectly The table on the right shows the resistance range of the outdoor unit thermistors at different temperatures

Resistance Values

ME Engineers App