I Application; Unit Components - Lennox CBX25UHV Series Installation And Service Procedure

HEAT JUMPER
The HEAT jumper is used to determine CFM during electric
heat operation only. These jumper selections are activated
only when W1 is energized.
DELAY JUMPER
The DELAY jumper is used to set the specific motor fan
operation during cooling mode. Depending on the
application, one of four options may be chosen by moving
the jumper to the appropriate set of pins.
#1 Pins Jumpered —
A Motor runs at 100% until demand is satisfied.
A
OFF
B Once demand is met, motor ramps down to stop.
#2 Pins Jumpered —
A Motor runs at 100% until demand is satisfied.
A
OFF
B Once demand is met, motor runs at 100% for 60
seconds.
C Motor ramps down to stop.
NOTE - Air Handler OFF DELAY also applies during
heat pump operation
#3 Pins Jumpered —
A Motor runs at 82% for approximately 7-1/2
minutes.
B If demand has not been satisfied after 7-1/2
minutes, the motor runs at 100% until demand is
satisfied.
A
OFF
C Once demand is met, motor ramps down to stop.
#4 Pins Jumpered —
A Motor runs at 50% for 30 seconds.
B Motor then runs at 82% for approximately 7-1/2
minutes.
C If demand has not been satisfied after 7-1/2
minutes, the motor runs at 100% until demand is
satisfied.
D Once demand is met, motor runs at 50% for 30
seconds.
E After 30 seconds at 50%, motor ramps down to
stop.
B
A
OFF
B
OFF
B
C
OFF
B C
OFF
C D
E
OFF
I-APPLICATION
Match all major blower coil components according to Lennox
recommendations, failure to comply voids warranty. Refer to
the Product Specification bulletin for approved system
matchups. Improperly matched systems result in erratic
operation and can result in early unit failure. The units come
with factory-installed check/expansion valve for all applications.
The TEV valve has been installed internally for a cleaner
installation and is accessible if required.
II-UNIT COMPONENTS
CBX25UHV PARTS ARRANGEMENT
Figure 2. Parts Arrangement
A-Control Box
The CBX25UHV control box is located above the blower
section 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, cover plates
cover the opening. The electric heat control arrangement is
detailed in the electric heat section of this manual.
B-Transformer
All CBX25UHV 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 40VA.
208/240VAC single phase transformers use two primary
voltage taps as shown in figure 3.
Page 10
ELECTRIC HEAT
SECTION (PLATE TO BE
REMOVED IF INSTALLED)
CONTROL BOX
BLOWER
HORIZONTAL DRAIN PAN
COIL
UPFLOW DRAIN PAN