Bryant 619E Installation, Start-Up And Service Instructions Manual page 15

3. When the room temperature is equal to or greater than
4° F below the selected temperature, the system oper-
ates as follows: The compressor and outdoor fan oper-
ate for 3 minutes. The indoor fan will operate at ultra-
low speed and will stop 30 seconds after the compressor
stops. After 4 or 5 minutes, the indoor fan starts in ultra-
low speed for 30 seconds. The normal dehumidification
operation is repeated for the newly sensed room tem-
perature. If the room temperature is still 4° F below the
selected temperature, the compressor, outdoor fan, and
indoor fan remain off. After 7
operates at ultra-low speed for 30 seconds. The normal
dehumidification operation is repeated for the newly
sensed room temperature.
• Heat Pump Heating Mode (Heat Pump Systems Only) —
When the Heat Pump mode is selected, the indoor fan will
operate at the selected speed if the speed is high, medium,
or low, unless overridden by the coil temperature (to pre-
vent cold drafts). If the indoor fan is in Auto. mode, the fan
will change operating speeds depending on the difference
between the room temperature, the set point, and the coil
temperature. The reversing valve will be deenergized.
The compressor cannot run for 3 minutes from the time
the system starts up or for 3 minutes from the time it last
40
30
DEFROST REGION TWO
(MINIMUM UNIT RUNTIME
= 6 HOURS*)
20
10
0
-10
-10
*A defrost will be initiated after 30 minutes of compressor run time if the outdoor
coil temperature is less than −4° F.
⁄ minutes, the indoor fan
1
2
DEFROST REGION THREE
0 10
OUTDOOR AIR TEMPERATURE (F)
Fig. 20 — Electronic Control Defrost Regions Map
operated. When the temperature of the room is 8° F below
the selected temperature, the unit will operate in Heat Pump
mode until the temperature is 6° F above the selected tem-
perature, or the compressor runs for 40 minutes (which-
ever comes first). If the temperature of the room is less than
7° F below or equal to the selected temperature, the unit
operates in Heat Pump mode until the selected set point
temperature plus 2° F is reached.
• Electric Heat in Heat Pump Heating Mode — Supplemen-
tal electric heat is enabled when the outside air ther-
mistor located in the outdoor unit is below 40 F and the
room temperature thermistor is equal to or less than 5.4 F
below set point. Electric heat will remain on until 1.8° F
above set point, then will turn off. Fan operation will be
the same as described previously in the heat pump heat-
ing mode.
NOTE: Electric heat control cannot be overridden.
• Demand Defrost Mode (Heat Pump Systems Only) — This
unit uses a demand defrost system to remove frost from
the outdoor coil during heating operation. The indoor and
outdoor fans are shut off during Defrost mode. See
Fig. 20. For high wall heat pump units, the electric heat is
OFF during Defrost mode.
(NO DEFROST OPERATION)
ADJUSTS IF LONG
DEFROST CYCLE
(MORE THAN
6 MINUTES)
DEFROST REGION ONE
(MINIMUM UNIT RUN TIME
= 50 MIN.*)
20
20
—15—
ADJUSTS IF SHORT
DEFROST CYCLE
(LESS THAN
3 MINUTES)
40