Lennox KCC Series Unit Information page 44

Power:
1 - Line voltage from unit disconnect energizes
transformer T1. T1 provides 24VAC power to
terminal strip TB1. TB1 provides 24VAC to the unit
cooling, heating and blower controls.
Blower Operation:
2 - VFD units are controlled by A96 inverter.
Economizer Operation:
3 - The economizer control module receives a demand
and energizes exhaust fan relay K65 with 24VAC at
50% outside air damper open (adjustable).
4 - N.O. K65-1 and N.O. K65-2 both close, energizing
exhaust fan motor B10.
Sequence of Operation
1st Stage Cooling (compressor B1)
5 - First stage cooling demand Y1 and G are energized
by the thermostat. G energizes blower. 24VAC is
routed through TB1 passing N.C. freezestat S49 and
optional N.C. high pressure switch S4. Compressor
contactor K1 is energized. N.O. contacts K1-1 close
energizing compressor B1. N.C. Contacts K1-2
open de-energizng crankcase heater HR1
6 - Contacts K10-1 close energizing condenser fan B4.
2nd Stage Cooling (compressor B2)
7 - 24VAC is routed through TB1 and proves N.C.
freezestat S50 and optional N.C. high pressure
switch S7. Compressor contactor K2 is energized.
N.O. K2 contacts close energizing compressor B2.
N.C.K2-2 opens de-energizing crankcase heater
HR2.
8 - N.O. contacts K10-1 close energizing condenser
fan B5.
Page 44