268723-BIM-C-0908
Johnson Controls Unitary Products
15
Operation
Anti-short Cycle Timer
This unit has an anti-short cycle timer built in to the defrost
control. This timer will not permit the compressor to start within
five minutes after the completion of the last cycle or power
interruption. To bypass the anti-short cycle feature, short the
“TEST” pins together for 2 seconds.
The following sequences of operation are based on using a
standard single-stage heat pump thermostat.
Cooling Sequence Of Operations
1.
When the fan switch on the thermostat is in the “ON”
position, the 24 volts at “G” will bring on the indoor blower
motor at the cooling airflow. When the fan switch on the
thermostat is in the “AUTO” position, the blower operates
only when there is a call for cooling by the thermostat.
2.
On a call for cooling, the thermostat sends 24 volts to “Y”
and “O” on the fan control and defrost control boards. The
reversing valve solenoid is energized, and after the anti-
short cycle period is complete contactor coil M1 is
energized. Power is supplied to the compressor and
outdoor fan motor, and the reversing valve switched to the
cooling position. When the fan switch on the thermostat is
in the “AUTO” position the indoor blower motor is
energized at the cooling airflow.
3.
When the demand for cooling has been satisfied, the
24 volt “Y” signal is removed, and the M1 contactor is de-
energized. When the fan switch on the thermostat is in the
“ON” position, the indoor blower motor continues to run. If
the fan switch is in the “AUTO” position. the indoor motor
ramps down over a 30-second period.
Table 10: Electric Heat Minimum Supply Air
Size
(Tons)
Voltage
Minimum Supply Air (CFM)
Heater kW
5.0
7.5
10.0
15.0
20.0
25.0
024
(2.0)
208/230-1-60
630
630
800
-
-
-
030
(2.5)
208/230-1-60
630
630
800
800
-
-
208/230-3-60
630
630
800
800
-
-
460-3-60
630
630
800
800
-
-
036
(3.0)
208/230-1-60
1070
1070
1070
1070
-
-
208/230-3-60
1070
1070
1070
1070
-
-
460-3-60
1070
1070
1070
1070
-
-
042
(3.5)
208/230-1-60
1225
1225
1225
1225
-
-
208/230-3-60
1225
1225
1225
1225
-
-
460-3-60
1225
1225
1225
1225
-
-
048
(4.0)
208/230-1-60
-
-
1200
1430
1430
1430
208/230-3-60
-
-
1200
1430
1430
1430
460-3-60
-
-
1200
1430
1430
1430
060
(5.0)
208/230-1-60
-
-
1615
1615
1955
1955
208/230-3-60
-
-
1615
1615
1955
1955
460-3-60
-
-
1615
1615
1955
1955
Table 11: Indoor Blower Specifications
Size
(Tons)
Motor
HP
RPM
Eff.
SF
Frame
024
(2.0)
1/2
Variable
0.8
1.0
48
030
(2.5)
1/2
Variable
0.8
1.0
48
036
(3.0)
3/4
Variable
0.8
1.0
48
042
(3.5)
3/4
Variable
0.8
1.0
48
048
(4.0)
3/4
Variable
0.8
1.0
48
060
(5.0)
1
Variable
0.8
1.0
48
Table 12: Electric Heat Multipliers
Voltage
kW Capacity Multipliers
1
1. Electric heaters are rated at nominal voltage. Use this table to determine the electric heat
capacity for heaters applied at lower voltages.
Nominal
Applied
240
208
0.75
230
0.92
480
460
0.92