Lennox CBX25UHV Series Installation And Service Procedure page 27

WARNING
USE COPPER CONDUCTORS ONLY
1. Disconnect all power supplies.
2. Remove the air handler access panel.
3. Route the field supply wires to the air handler electrical
connection box.
4. Use UL-listed wire nuts to connect the field supply
conductors to the unit black and yellow leads, and the
ground wire to ground terminal marked GND.
5. Replace the air handler access panel.
208 VOLT CONVERSION
1. Disconnect all power supplies.
2. Remove the air handler access panel.
3. Using the wiring diagram located on the unit access
panel as a reference, move the black transformer leads
from the 240-volt terminal on the transformer to the
208-volt terminal on the transformer.
See figure 36.
208 / 240 VOLT TRANSFORMER
240 Volts
Figure 36. Converting Unit from 240 VAC to 208 VAC
POWER UP — LINE VOLTAGE
With Electric Heat — 240VAC line voltage power is
supplied from the circuit breaker to the heat strips and
control section via the 6-pin plug. (terminals 1 and 2).
Without Electric Heat — 240VAC line voltage is supplied
from the black and yellow wires from the 6-pin plug to the
control section.
Blower Motor — 240VAC is supplied to the blower motor
through pins 4 and 5 of the 5-pin plug.
NOTE - Blower relay coil is energized when SEQ1 relay
normally open contacts (4 to 5) close.
Transformer — 240VAC is supplied to the transformer
primary from L1 and L2.
Page 27
PRIMARY SECONDARY
208 Volts