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I–APPLICATION
All major blower coil components must be matched
according to Lennox recommendations for the unit to
be covered under warranty. Refer to the Engineering
Handbook for approved system matchups. A misapplied
system will cause erratic operation and can result in early
unit failure. The units come with factory installed check
and expansion valve for all applications. The TXV valve
has been installed internally for a cleaner installation and
is accessible if required.
II–UNIT COMPONENTS
A–Control Box
The CB29M and CB30M control box is shown in figure
2. Line voltage and electric heat connections are made
in the control box. Optional electric heat fits through an
opening located in the center of the control box. When
electric heat is not used, knock out plates cover the
opening. The electric heat control arrangement is detailed
in the electric heat section of this manual.
B–Door Interlock Switch (S51)
(460 and 575 volt only)
All CB29M and CB30M 460/575 volt units are
equipped with a door interlock switch (S51). The
switch is rated at 14A at 125VAC and is located on the
edge of the control box (see figure 2). The switch is
wired in series with terminal strip (TB1). When the
blower door is removed the unit will shut down.
C–Terminal Strip (TB1)
All CB29M and CB30M units are equipped with a low
voltage terminal strip (TB1) located in the control box.
See figure 2. The strip is used for making up all indoor
thermostat wires. The outdoor unit low voltage wiring
connections may be spliced with wire nuts inside the
CB units.
D–Transformer (T1)
All CB29M and CB30M series units use a single line
voltage to 24VAC transformer mounted in the control
box. The transformer supplies power to the control
circuits in the indoor and outdoor unit. Transformers
are rated at 70VA. 208/240VAC single phase transformers
use two primary voltage taps as shown in figure 3.
FIGURE 3
BLUE
YELLOW
ORANGE
RED
BLACK
240 VOLTS
208 VOLTS
PRIMARY
SECONDARY
208 / 240 VOLT TRANSFORMER
CB8
E–Circuit Breaker (CB8)
All transformers used in the CB29M and CB30M series
units are equipped with internal secondary voltage
overcurrent protection. Each transformer uses a circuit
breaker (CB8) located on the transformer. The circuit
breaker is connected in series with the blue secondary
voltage wire and is rated 3.5 Amps.
F–Auto Transformer (T26) (575 volt only)
All CB29M and CB30M 575 volt units use a 575VAC to
460VAC step down transformer mounted in the control
box (see figure 2). The transformer comes with the 575
volt electric heater and is connected to the unit via jack/
plugs J/P50 and J/P92. The transformer supplies 460VAC
to transformer T1 and blower motor B3.
G–Transformer Fuse (F33) (575 volt only)
All T26 auto transformers are protected by two inline
fuses (F33). Both of the fuses are rated at 600 volts
and 3.2 amps.
H–Blower Relay (K3)
All CB29M and CB30M units use a DPDT relay to ener-
gize the blower motor. The relay coil is energized by
blower demand from indoor thermostat. When the
coil is energized, a set of N.O. contacts closes to energize
the blower motor on cooling speed. When de–energized,
a set of N.C. contacts allows the optional electric heat
relay to energize the blower on heating speed (refer to
unit wiring diagram).
Содержание CB29M-21
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