ECSS E3335
- 25 -
CONTROL OPERATION
Electronic Control
This unit is equipped with a CAREL PJEZ temperature control. The control parameters
are set at the factory and cannot be manually changed in the field. Control parameter
changes can only be made by downloading a new set of parameters via a program chip
supplied by Federal Industries.
Operation
The control uses two sensors, one located in the air stream and one located on the
evaporator coil. The sensor located in the air stream is referred to as the temperature
control sensor. The sensor located on the evaporator coil is referred to as the coil
sensor.
The temperature control sensor is located inside the center tower at the top. The sensor
location is critical for proper operation on the unit. Do not move or relocate this sensor.
The coil sensor is strapped to the evaporator coil. This sensor location is critical for
proper operation of the unit. Do not move or relocate this sensor.
The temperature control is set to cut in at 39 degrees F. The Temp control cuts out at
14 degrees F at the coldest setting “9” and 28 degrees F at the warmest setting, ‘1’ on
the control display.
The temp control turns off the refrigeration system when you “press and hold” the top
arrow / power button for approx. 3 seconds until “OFF” flashes on display.
Defrost Cycle
The CAREL control is programmed to initiate defrost via two different methods. There
are 3 programmed defrost cycles in the case which will initiate a defrost cycle every 8
hours. The unit does not have a time clock so the defrost cycles cannot be set for any
specific time of day.
The unit also has an ‘On demand’ defrost feature that will initiate a defrost when the
temperature differential between the evaporator temperature and the air temperature is
more than 15 degrees for 5 minutes after 30 minutes into the refrigeration cycle.
Maximum Run Timer
The unit is equipped with a maximum run timer that is preset at the factory for 75
minutes on. If the temperature control does not reach cut out set point after running for
one hour, the timer will turn the compressor off for a minimum of 2 minutes.
