Powering and Starting the Unit - Follow the Instructions on Page 6 of this manual.
1. Make sure that the power supplied to the OPACH4212 unit matches the power shown on the
unit nameplate, and that all power connections are correct and secured.
NOTE: Connecting the unit to an incorrect or faulty power source will void the warranty
2. Engage the MAIN POWER. The unit is now controlled by the thermostat.
Cooling Mode
Begin by pressing the SYSTEM button until the thermostat is in COOL Mode. Using the
ARROW buttons, set the desired space temperature setpoint. Remember, cooling will begin
once the space temperature has risen 3 degrees above the set point.
NOTE: The minimum setpoint in Cooling Mode is 55 degrees F
Heating Mode
Begin by pressing the SYSTEM button until the thermostat is in HEAT Mode. Using the
ARROW buttons, set the desired space temperature setpoint. Remember, heating will begin
once the space temperature has fallen 3 degrees below the set point. When in Heat Mode,
the thermostat determines the heating operation according to a preprogrammed switch-over
temperature.
When in HEAT mode, the unit will operate in Heat Pump mode until the outdoor temperature
falls below the preprogrammed limit of 50 degrees. The unit will automatically switch to
Electric Auxiliary Heat until the outdoor temperature rises above 50 degrees.
Fan Mode
Pressing the FAN button, allows the user to switch Fan Modes from AUTO to ON. In AUTO
Mode, the fan will turn on and off as the unit cycles in Cooling or Heating Mode. In ON Mode,
the fan will run continuously.
Circuit Breakers
The unit and the Auxiliary Heat Module are protected by line power circuit breakers.
The unit breaker will trip at 50 Amps, while the Auxiliary Heat Module is protected by a separate
40 Amp breaker, located behind the Blower Cover Panel. The control access cover and blower
access panel will need to be removed to gain access to the heater breaker as shown on Page 7.
Model Number:
MODEL: OPACH4212
OPACH4212 START UP AND OPERATION
OA-EISM-OPACH4212- REV. 04062023
Page 9
