Lennox LGT Series Unit Information page 17

PLUMBING, COMPRESSOR AND REFRIGERANT CIRCUITS DETAIL
Discharge Line
Discharge Line
Stage 2
Low Pressure Switch
High Pressure
Switch
S7
High Pressure
Switch
S4
B-Cooling Components
High efficiency units use independent cooling circuits
consisting of separate compressors, condenser coils and
evaporator coils. See figure 6. Units are equipped with
ECM direct drive blowers which draw air across the evap-
orator during unit operation.
On all units the evaporators are slab type and are row split.
Each evaporator uses a thermostatic expansion valve as
the primary expansion device.
In all units, each compressor is protected by a crankcase
heater, high pressure switch and low pressure switch. Ad-
ditional protection is provided by by thermistors for low
ambient control and freezing prevention.
Cooling may be supplemented by a factory- or field-in-
stalled economizer.
Suction Line
Suction Line
Stage 2
Stage 1
Stage 1
S88
Compressor
B1
Compressor
B2
FIGURE 6
1-Compressors B1, B2
Units are equipped with two scroll compressors and two
independent cooling circuits. B1 is 2-stage compressor,
with L34 to switching between part load and full load, B2
is single stage compressor. Compressor capacity may
vary from stage to stage. In all cases, the capacity of each
compressor is added to reach the total capacity of the unit.
See "SPECIFICATIONS" and "ELECTRICAL DATA" (ta-
ble of contents) or compressor nameplate for compressor
specifications.
Electrical shock hazard. Compressor must be
grounded. Do not operate without protective
coverover terminals. Disconnect power before
removing protective cover. Discharge capacitors
before servicing unit. Failure to follow these
precautions could cause electrical shock resulting
in injury or death.
Page 17
Evaporator Coil
Low Pressure Switch
S87
WARNING