Service Manual -
HRG18xxS1P
508206-01
Issue 2140
Page 66 of 83
LOW AMBIENT OPERATION:
The HRG18 units have factory installed low ambient cooling mode operation that will control the condenser fan motor
based upon liquid line temperature.
The HRG18 units have a variable speed ECM fan motor. The outdoor control will begin to modulate the outdoor fan motor
speed is below 65°F to maintain a liquid line sensor temperature between 58°F and 70°F. If the liquid line sensor drops
below 55°F the control will cycle the fan off until liquid temperature rises above 58°F.
CHECKOUT:
VAC Voltage Check
Check for 208/240 VAC power at inverter contactor (red wires) (see Figure 40).
To exit, push and hold the button until three horizontal bars display. Release the button and the outdoor fan will cycle off.
Units with ECM Motor
1. With the unit running, check for 230VAC at the red outdoor fan motor wires at the contactor. If no voltage is present
check main power at the contactor.
2. Perform a DC voltage check between the FPWM and Fan C terminal.
3. Using the push button on the control, enter the “fan test mode” in the “field test mode” by pushing and holding the button
until solid “-” appears, release the button. Display will start flashing, within 10 seconds, push and hold the button until
the “F” symbol displays then release the button. Display will begin to flash “F”, within 10 seconds, push and hold the
button until it stops flashing, release the button. Outdoor fan motor will cycle on for 10 minutes. To exit, push and hold
the button until three horizontal bars display. Release the button and the outdoor fan will cycle off.
FAN PWN AND COM
TERMINAL USED ON
VARIABLE SPEED
FAN MOTOR
Figure 40. VAC Voltage Check