Page 37
LGH/LCH036, 048, 060, 072
TABLE 28
APPROACH TEMPERATURE
LGH/LCH Unit Liquid Temp. Minus Ambient Temp.
036S & H Std.
036S & H Reheat
048H Std.
060S & H Reheat
060H Std.
072H Std.
6°F + 1 (3.3°C + 0.5)
048H Reheat
072H Reheat
7°F + 1 (3.9°C + 0.5)
048S Std.
060S Std.
8°F + 1 (4.4°C + 0.5)
048S Reheat 9°F + 1 (5.0°C + 0.5)
E-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 (3275kPa + 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- Freezestat (S49)
The compressor is protected by a freezestat located
on the indoor coil. The freezestat opens at 29F+
3
(-2C+2) and closes at 58F+4 (14C+2).
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.
5- Low Ambient Pressure Switch (S11)
Switch maintains adequate discharge pressure by
de-energizing condenser fan when liquid pressure
falls below 240 psig +
10 (1655 kPa+69). S11 is
installed in the liquid line. Switch closes to energize
condenser fan when pressure rises to 450 psig +
10
(3103kPa +
69).
6- Discharge Line Thermostat (S40)
3 through 5 Ton Units Only
Switch opens when discharge line temperature
reaches 94F+
5 (34C+3) and closes when
temperature falls below 74F+
5 (23C+3). Prevents
crankcase heater operation in warm weather.
7- High Ambient Pressure Switch (S16)
Switch improves high ambient operation by
activating the TXV assist circuit. Switch closes at
550psig +
10 (3792kPa + 70kPa) and automatically
resets at 400 PSIG (2758kPa +
70kPa).
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