COOLING SYSTEM
The cooling section is a complete factory package utilizing an
air-cooled condenser. The system is factory-charged with
Refrigerant-22.
The compressors are hermetically sealed, internally sprung
and base-mounted with rubber-insulated hold-down bolts.
The compressors also have inherent (internal) protection. If
there is an abnormal temperature rise in a compressor, the
protector will open to shut down the compressor.
PRELIMINARY OPERATION COOLING
After installation has been completed, energize the crankcase
heaters for at least four hours before operating unit. After this
initial warm-up, the compressors should be given three false
starts (energized just long enough to make a few revolutions)
with 5-7 minutes delay between each start before being put into
full time service.
NOTE: Prior to each cooling season, the crankcase heaters
must be energized at least 10 hours before system is
put into operation.
COOLING SEQUENCE OF OPERATION
When the thermostat calls for “first-stage” cooling, the low
voltage control circuit from “R” to “G” and “Y1" (wiring
schematic) is completed to energize compressor #1,
condenser fan motor #1 and blower motor simultaneously.
When the thermostat calls for “2nd-stage” cooling, the low
voltage control circuit from “R” to “Y2" is completed to energize
compressor #2 and condenser fan motor #2.
After the thermostat is satisfied and opens, all components
likewise stop simultaneously.
CONTINUOUS BLOWER - Continuous blower operation is
possible by closing the R to G circuit on the thermostat.
SAFETY CONTROLS
Each refrigerant system is equipped with the following safety
controls:
1. A Suction Line Freezestat to protect against low evaporator
temperatures due to a low air flow or a low return air
temperature. (Opens at 26
°
F + 5
°
F and resets at 38
°
F +
5
°
F).
2. A High Pressure Cutout Switch to protect against excessive
discharge pressures due to a blocked condenser coil or a
condenser motor failure. (Opens at 380 psig + 10 and
resets at 300 psig +10).
3. A Low Pressure Switch/Loss Of Charge to protect against
loss of refrigerant charge. (Opens at 7 psig + 3 and resets
at 22 psig + 5).
If either one of the above safety controls opens, that individual
refrigerant system will bo locked out. The other refrigerant
system will continue in operation unless it too is effected by the
same fault. The lock out of either system can be reset by
opening the 24V circuit either at the room thermostat or at the
unit disconnect.
HEATING SEQUENCE OF OPERATION
The following sequence describes the operation of the gas heat
section.
CONTINUOUS BLOWER: With the room thermostat switch set
to “ON”, the supply air blower will operate continuously. The
normally closed contact “K5-1" provides 24 volt power to the
“3M” relay. The “3M-1” and “3M-2" power contacts close and
the blower motor operates.
INTERMITTENT BLOWER: With the room thermostat
system switch set to the “AUTO” or “HEAT” position and the
fan switch set to “AUTO”, the supply air blower will operate
after the room thermostat calls for heat and the time delay
relay closes.
OPERATION
MODEL
POWER
SUPPLY
COMPRESSOR
(#1 and #2)
OUTDOOR
FAN
MOTOR,
(#1 & #2)
FLA
EACH
SUPPLY
AIR
BLOWER
MOTOR,
FLA
TOTAL
UNIT
AMPACITY,
AMPS
MAX.
FUSE
SIZE
1
AMPS
MAX.
HACR
BREAKER
SIZE,
AMPS
MIN.
WIRE
SIZE,
2
AWG
RLA
EACH
LRA
EACH
2HP 3HP 5HP 2HP 3HP 5HP
2HP 3HP 5HP
D3CG090
208/230-3-60
460-3-60
575-3-60
14.1
7.1
5.8
130
64
52
2.3
1.3
1.3
7.5
3.4
2.7
-
-
-
-
-
-
43.8
21.9
18.3
-
-
-
-
-
-
50
25
20
50
25
-
8
12
14
-
-
-
-
-
-
D3CG102
208/230-3-60
460-3-60
575-3-60
16.0
8.3
7.1
137
69
58
2.3
1.3
1.3
7.5
3.4
2.7
10.6
4.8
3.9
-
-
-
48.2
24.8
21.2
51.3
26.2
22.4
-
-
-
60
30
25
60
30
-
8
12
12
6
10
12
-
-
-
D3CG120
208/230-3-60
460-3-60
575-3-60
16.7
9.6
8.3
150
73
62
2.3
1.3
1.3
7.5
3.4
2.7
10.6
4.8
3.9
-
-
-
49.6
27.6
24.1
52.7
29.0
25.3
-
-
-
60
35
30
60
35
-
8
10
12
6
10
10
-
-
-
D4CG150
208/230-3-60
460-3-60
575-3-60
21.8
9.6
9.0
158
79
65
3.5
2.5
2.5
-
-
-
10.6
4.8
3.9
15.1
7.5
5.9
-
-
-
66.6
31.4
29.1
71.1
34.1
31.1
80/90
40
35/40
90/100
50
-
-
-
-
4
8
8
4
8
8
NOTES:
1. Dual element, time delay type. Amps shown as “80/90" indicates rating for 3 HP / 5 HP, respectively.
2. Based on 75
°
C copper conductors.
TABLE 9 - ELECTRICAL DATA
530.18-N10Y
12
Unitary Products Group
