Carrier 69NT40-561-201 Operation & Service Manual

3−8T-364ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍController Set Point at or BELOW −10°C (+14°F),−.20°C+.20°CAir CirculationCooling,EconomizedSet Point+2.5°C(+4.5°F)Frozen ModeFallingTemperatureRisingTemperatureFigure 3−8 Controller Operation - Frozen Mode3.3.15 Frozen “Heat” ModeIf the temperature drops 10C (18F) below set point,the unit will transition to the frozen “heat” mode. Theevaporator fans are brought to high speed, and the heatfrom the fans is circulated through the container. Theunit will transition back to frozen steady state when thetemperature rises back to the transition point.3.3.16 Frozen Mode Cooling - Sequence ofOperationa. When the return air temperature is above set pointand decreasing, the unit will transition to economizedcooling with the condenser fan motor (CF), com-pressor motor (CH), economizer solenoid valve(ESV), low speed evaporator fan motors (ES) ener-gized and the blue COOL light illuminated. (SeeFigure 3−9).b. When the return air temperature decreases to a pre-determined tolerance above set point, the green IN-RANGE light is illuminated.c. When the return air temperature decreases to 0.2C(0.4F) below set point, contacts TC, TS and TN areopened to de-energize the compressor, economizersolenoid valve and condenser fan motor. The blueCOOL light is also de-energized. The EEV will close.d. The evaporator fan motors continue to run in lowspeed to circulate air throughout the container. Thegreen IN-RANGE light remains illuminated as long asthe return air is within tolerance of set point.e. If return air temperature drops to 10C (18F) ormore below set point, the evaporator fans increase tohigh speed.f. When the return air temperature increases to 0.2C(0.4F) above set point and three minutes haveelapsed, the EEV opens and contacts TC, TS and TNclose to restart the compressor, open the ESV andrestart the condenser fan motor. The blue COOL isilluminated.