I Unit Components - Lennox KGC Series Unit Information

I-UNIT COMPONENTS
All 7.5 through 12.5 ton (26.3 through 44 kW) units are
configure to order units (CTO). The KGC unit components
are shown in figure 1. All units come standard with remov-
able unit panels. All L1, L2 and L3 wiring is color-coded;
L1 is red, L2 is yellow and L3 is blue.
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic
electronic components. Take precautions
to neutralize electrostatic charge by
touching your hand and tools to metal
prior to handling the control.
A-Control Box Components
KGC control box components are shown in FIGURE 2.
The control box is located in the upper portion of the com-
pressor compartment.
1-Disconnect Switch S48
All units may be equipped with an optional disconnect
switch S48 or circuit breaker CB10. S48 and CB10 are
toggle switches, which can be used by the service techni-
cian to disconnect power to the unit.
2-Control Transformer T1
All use a single line voltage to 24VAC transformer installed
in the control box. The transformer supplies power to con-
trol circuits in the unit. The transformer is rated at 70VA
and is protected by a 3.5 amp circuit breaker (CB8). The
208/230 (Y) voltage transformers use two primary voltage
taps as shown in figure 4, while 460 (G) and 575 (J) volt-
age transformers use a single primary voltage tap.
208/230V TRANSFORMER
BLUE
SECONDARY
PRIMARY
ORANGE
FIGURE 3
3-C. A. I. Transformers T3 575V Only
All KGC 575 (J) voltage units use transformer T3 located
in the control box. The transformers have an output rating
of 0.5A. T3 transformer supplies 230 VAC power to the
combustion air inducer motor (B6).
discharge can
YELLOW
208 VOLTS
RED
230 VOLTS
BLACK
4-Terminal Strip TB1
All indoor thermostat connections are made at terminal
block TB1 located in the control area. For thermostats
without "occupied " and "unoccupied" modes, a factory-in-
stalled jumper across terminals R and OC should be in
place.
5-Condenser Fan Capacitors C1 & C2
Fan capacitors C1 and C2 are used to assist in the start
up of condenser fans B4 and B5. Ratings will be on side
of capacitor or outdoor fan motor nameplate.
affect
6-Compressor Contactor K1 & K2
All compressor contactors are three-pole-double-break
contactors with 24VAC coils. In all KGC units, K1 and
K2 energize compressors B1 and B2 in response to
thermostat demand. See FIGURE 4.
7-Blower Contactor K3
Blower contactor K3, used in all units, is a three-poledou-
ble- break contactor with a 24VAC coil used to energize
the indoor blower motor B3 in response to blower de-
mand. K3 is energized by a thermostat cooling demand.
See FIGURE 4.
8-Condenser Fan Relay K10
Outdoor fan relay K10 is a DPDT relay with a 24VAC coil.
K10 energizes condenser fans B4 and B5.
9-Power Exhaust Relay K65 (PED units)
Power exhaust relay K65 is a DPDT relay with a 24VAC
coil. K65 is used in all units equipped with the optional
power exhaust dampers. K65 is energized by the econo-
mizer enthalpy control A6, after the economizer dampers
reach 50% open (adjustable) When K65 closes, exhaust
fan B10 is energized.
Page 14
CONTACTOR
FIGURE 4