I Unit Components - Lennox LCH092H Unit Information

I-UNIT COMPONENTS
All 7.5 through 12.5 ton (38.1 through 70.3 kW) units are
configure to order units (CTO). The LCH unit components
are shown in figure 1. All units come standard with hinged
unit panels. All L1, L2, and L3 wiring is color coded; L1 is red,
L2 is yellow, and L3 is blue.
A-Control Box Components
CAUTION
Electrostatic discharge can affect elec­
tronic components. Take precautions to
neutralize
touching your hand and tools to metal
prior to handling the control.
LCH standard and high efficiency units control box compo­
nents are shown in figure 3. Ultra units control box compo­
nents are shown in figure 4. The control box is located in the
upper portion of the compressor compartment.
1-Disconnect Switch S48 (Optional)
All units may be equipped with an optional disconnect switch
S48. Other factory or field installed optional circuit breakers
may be used, such as CB10. S48 and CB10 are toggle
switches, which can be used by the service technician to dis­
connect power to the unit.
2-Control Transformer T1
All use a single line voltage to 24VAC transformer mounted
in the control box. Transformer supplies power to control
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 primary voltage taps as
shown in figure 5, while 460 (G) and 575 (J) voltage trans­
formers use a single primary voltage tap.
208/230V TRANSFORMER
BLUE
SECONDARY
ORANGE
3-Outdoor Fan Capacitors C1, C2 (non-Ultra
units)
Fan capacitors C1 and C2 370V / 10 MFD capacitors are
used to assist in the start up of condenser fans B4 and B5.
electrostatic charge
YELLOW
208 VOLTS
RED
230 VOLTS
PRIMARY
BLACK
FIGURE 5
4-Compressor Contactor K1, K2
All compressor contactors are three‐pole, double‐break
contactors with 24VAC coils. In all LCH units, K1 and K2
(both energized by A55) energize compressors B1 and B2.
On CE M-volt units, contactor is CE approved by manufac­
turer (Siemens). See figure 6.
by
5-Blower Contactor K3
K3 is used in units with a constant blower speed or a staged
blower which is not equipped with a bypass option. K3 is a
three‐pole‐double‐break contactor with a 24VAC coil used
to energize the indoor blower motor B3 in response to blow­
er demand. K3 is energized by A55 Unit Controller. On
M-volt CE units, the contactor is CE approved by manufac­
turer (Siemens). See figure 6.
6-Outdoor Fan Relay K10, K68 (non-Ultra
units)
Outdoor fan relays K10 and K68 are DPDT relays with a
24VAC coil. In all LCH units K10 and K68 energize condenser
fans B4 and B5.
7-Power Exhaust Relay K65 (PED units)
Power exhaust relay K65 is a N.O. DPDT relay with a
24VAC coil. K65 is used in all LCH units equipped with the
optional power exhaust dampers. K65 is energized by the
economizer control panel (A56), after the economizer
dampers reach 50% open (adjustable in ECTO). When K65
closes, the exhaust fans B10 and B11 are energized.
8-Unit Controller A55
The Unit Controller provides all unit control functions, unit
status information, unit diagnostics, programmable pa­
rameters and USB verification and profile sharing. Use the
Unit Controller keypad and display to navigate through
menus. Software is also available to access the Unit Con­
troller. Refer to the Unit Controller guide provided with the
unit. Thermostat wires are connected to J297 on the Unit
Controller.
Page 34
CONTACTOR
FIGURE 6