Lennox M33A036S4-1P - EC Fault Code

Lennox Mini-Split Service Manual / Page 208
EC Fault Code
Basic Description:
Low refrigerant error.
General Note:
The system monitors the value of evaporator coil sensor T2 for the fi rst 5 minutes
after startup. If the temperature of T2 drops per this formula three times in the fi rst 5
minutes of operation, the system shuts down and the error code displays.
For this formula “Tcool” = the T2 temperature at startup.
T2 < Tcool - 3.6°F (2°C)