Page 29
LGT/LCT036, 048, 060, 072
TABLE 12
072 NORMAL OPERATING PRESSURES - REHEAT - ALL-ALUMINUM COIL - 581111-01
Outdoor Coil Entering Air Temperature
65
F
75
F
85
F
95
F
105
F
115
F
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
Suct
(psig)
Disc
(psig)
108
276
109
316
111
363
113
418
116
480
118
550
116
281
118
320
120
367
123
422
125
484
128
554
135
294
137
332
140
379
143
432
146
494
149
563
156
310
158
348
161
394
165
447
168
508
172
576
072 CHARGING CURVE - REHEAT - ALL-ALUMINUM COIL - 581111-01
Suction Pressure (psig)
70
80
90
100
110
120
105
115
125
135
145
155
Outdoor Temperature (°F)
165
175
105°
95°
115°
85°
75°
65°
60
130
C-Compressor Controls
See unit wiring diagram to determine which controls are
used on each unit. Optional controls are identified on
wiring diagrams by arrows at junction points.
1- High Pressure Switch (S4)
The compressor circuit is protected by a high
pressure switch which opens at 640 psig + 10 psig
(4413 kPa + 70 kPa) and automatically resets at 475
psig + 20 psig (3 138 kPa).
2- Low Pressure Switch (S87)
The compressor circuit is protected by a loss of
charge switch. Switch opens at 40 psig + 5 psig (276
+ 34 kPa) and automatically resets at 90 psig + 5
psig (621 kPa + 34 kPa).
3- Diagnostics Sensors (RT46, RT48)
Two thermistors are located on specific points in the
refrigeration circuit. The thermistors provide constant
temperature feedback to the Unit Controller to protect
the compressor. Thermistors take the place of the
freezestat and low ambient pressure switch.
4- Compressor Crankcase Heater (HR1)
Crankcase heater must be energized at all times to
prevent compressor damage due to refrigerant
migration. Energize crankcase heater 24 hours before
unit start-up by setting thermostat so that there is no
cooling demand (to prevent compressor from cycling)
and apply power to unit.
