Page 14
I-UNIT COMPONENTS
WARNING
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or maintenance, turn the
electrical power to unit OFF at disconnect
switch(es). Unit may have multiple power
supplies.
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
electronic components. Take precautions
to neutralize electrostatic charge by
touching your hand and tools to metal
prior to handling the control.
The LDT unit parts arrangement are shown in FIGURE
yellow, and L3 is blue. See wiring diagrams in the back of
this manual for complete call out of components per LDT
A-Control Box Components
LDT control box components are shown in FIGURE 2. The
control box is located in the upper portion of the compres-
sor compartment.
1-Disconnect Switch S48 (Optional)
All units may be equipped with an optional disconnect
breakers may be used, such as 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 mount-
ed in the control box. Transformer supplies power to con-
trol circuits in the unit. The transformer is rated at 92VA
voltage transformers use a single primary voltage tap.
BLUE YELLOW
ORANGE
RED
BLACK
230 VOLTS
208 VOLTS
PRIMARY
SECONDARY
FIGURE 3
3-C. A. I. Transformers T3 575V Units
voltage to 230VAC transformer is mounted in the control
transformer supplies 230 VAC power to combustion air
4-Transformer T18
T18 is a single line voltage to 24VAC transformer used in
all LDT units. T18 is rated at 70VAC and is protected by a
5-Compressor Contactor K1, K2
All compressor contactors are three-pole, double-break
contactors with 24VAC coils. K1 and K2 (both energized
6-Power Exhaust Relay K65 (PED units)
7-Terminal Block (TB13)
TB13 terminal block distributes line voltage power to the
line voltage items in the unit.
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