Wiring Diagrams / Operation Sequence - Lennox LGA Series Unit Information

The supply air VFD (A96) is located near the compressors.
See figure 39.
Excessive Duct Static
The IMC will lock−out the unit for 5 minutes if static pressure
exceeds 2.0"w.c. for 20 seconds. The IMC will permanently
shut down the unit after three occurrences. See IMC ECTO
5.02, 0.21, and 0.22 to adjust default values.
Optional field−installed high pressure switch (S155) will de−
energize the unit above static pressure setpoint. Refer to
B3 blower VFD wiring diagram. Set cut−out pressure at
2"w.c. unless otherwise specified. Switch must be manual-
ly reset.
SUPPLY AIR VARIABLE FREQUENCY DRIVE
FIGURE 39
Supply Air VFD By−Pass Plug (Optional)
The supply air VFD may be by−passed using jack/plug con-
nections. Locate J/P198 connectors in control box area un-
der the relays. Disconnect J198 from P198 and connect
J204 or J206 to P198. See figure 40. Blower will operate in
constant air volume mode.
VII−WIRING DIAGRAMS AND
The following pages contain the wiring diagrams for LGA/
LGC/LCA/LCC248/360 series units. An economizer and
thermostat are also shown. Each wiring diagram is fol-
lowed by a sequence of operation.
SUPPLY AIR
VFD (A96)
Page 64
SUPPLY AIR VFD BY−PASS CONNECTOR
CONNECTORS USED
FOR SUPPLY AIR
VFD OPERATION
J198
P198
FIGURE 40
OPERATION SEQUENCE
CONNECTORS USED TO
BY−PASS VFD AND
OPERATE SUPPLY AIR
BLOWER IN CONSTANT
AIR VOLUME
J204
or
J206
P198