11
Heating — Lower the thermostat setpoint
temperature to the lowest obtainable setting and
set the thermostat function switch to HEATING.
The indoor blower and outdoor unit should stop
running. After a minimum of five minutes, increase
the setpoint temperature of the thermostat to the
maximum setting. Verify that the outdoor unit and
indoor blower have energized. Feel the air being
circulated by the indoor blower and verify that
it is warmer than ambient temperature. Listen
for any unusual noises. If present, locate and
determine the source of the noise and correct
as necessary.
OUTDOOR THERMOSTAT (if supplied)
The outdoor thermostat prevents the electrical
auxiliary heat (if used) from operating above a
desired set point. Selection of the set point is
determined from the building design heat load.
The thermostat is adjustable from 45°F to 0°F.
The factory temperature setting is at 40°F.
Defrost Cycle Timer — The defrost cycle timer
controls the time interval of the hot gas defrost
after the defrost sensor closes. It is located
in the lower left corner of the defrost control
board. Three interval settings are available: 30
minutes, 60 minutes, and 90 minutes. Time setting
selection is dependent on the climate where the
unit is being installed.
Example 1. Dry climate of Southern
Arizona. A 90 minute setting is
recommended.
Example 2. Moist climate of Seattle,
Washington. A 30 minute setting is
recommended.
To set the cycle timer, place the timing pin on
the defrost control board to the desired time
interval post.
Note: All units are shipped from the factory with
the default time setting of 30 minutes. Maximum
heating performance can be achieved by setting
the time to 90 minutes.
DEFROST CONTROL BOARD OPERATION
AND TESTING
1. Terminals “R”-”C” must have 24±V present
between them in order for the time delay and
defrost sequences to be operational.
2. Jumper the “T2”-”DFT” test pins. This will
indicate to the board that the defrost T-stat
is closed(if the compressor is running).
Defrost T-stat is closed at 32° or below and
is open at 68° or above. But it’s state is
unknown if the temperature is between 32°F
and 68°F. The defrost thermostat tells the
board whether a defrost cycle needs to be
started or terminated. With the DFT closed
the unit will run for 30/60/90 minutes in heat
mode and then defrost the outdoor coil. The
defrost will turn off the outdoor fan, turn on the
compressor and raise the coil temperature to
68°F. This will open the DFT and terminate
the defrost. If the DFT does not open the
defrost will end after 10 minutes.
Figure 2. Comfort Alert
TM
Diagnostics Module
POWER LED
(Green)
TRIP LED
(Red)
ALERT LED
(Yellow)
Diagnostics
Key
