When the air temperature decreases to a predetermined tolerance above set point, relay TI energizes and the
(Refer to section 3.1.4, Code 30.)
If the air temperature continues to fall, modulating cooling starts at approximately 2.5_C (4.5_F) above set point. The modulating valve will have a variable current up to 1.30 amps at full modulation.
During this cooling mode, a running sum of the temperature differential (supply air temperature minus the set point) is kept. When the supply air falls below set point, the differential is negative. The longer supply air remains below set point, the greater the differential in the running sum.
When the supply air temperature decreases to 0.2_C below set point and the running sum is less than
shutting off the condenser fan and compressor motors. Also, the cool light is
The evaporator fan motors continue to run to circulate air throughout the container. The
If the unit is in the holding mode (neither heating nor cooling) and the supply air temperature increases to 0.2_C (0.4_F) above set point, and providing a six minute off time has elapsed, relay TC energizes to restart the compressor. Also, at this time, the condenser fan motor starts and the cool light is illuminated.
During this mode the dual speed compressor can be either running in high or low speed depending on the box load. Refer to Figure
|
