Holding Cabinet – Service Manual
5
SEQUENCE OF OPERATION
Power Supply
Electrical power is supplied to the unit by a 3 conductor service for single
phase.
120VAC
Black conductor is hot.
White conductor is neutral.
Green and yellow conductor is ground.
Power is permanently supplied to the main power switch.
Heating Circuit
Closing the main power switch supplies voltage to the power board and user
interface.
Temperature is set through the user interface which then intermittently
supplies 120VAC to the heater plates. Temperature is then controlled by the
thermocouples sending a reference signal back to the user interface.
