Cooling Operation - Lennox CBX40UHV Series Installation And Service Procedure

3. Cooling Operation

Air Handler Control AHC) Indoor Blower Mode Speed and Profiles
settings
1. Set Cooling Mode Blower Speed jumper pin.
2. Set Cooling Mode Blower Ramping jumper pin.
3. Set Blower Adjust Selection jumper pin.
Single or Two-Stage Unit
AHC on-board link must be cut between Y1 and Y2 to allow 2 stage cooling operation.
RECOMMEND - USE FIGURE 11 AS A REFERENCE
FOR SETTING JUMPER CONFIGURATIONS ON THE
AIR HANDLER CONTROL.
Air Handler Control (AHC) receives inputs on Y1 terminal.
Y1 terminal on AHC is configured as input and passes
signal from room thermostat to outdoor unit.
NOTE - The outdoor unit control directly controls the
outdoor unit operation.
Y1 input to the AHC will control the indoor blower
according to the cooling or heating mode blower speed,
ramping and adjust selection jumper pins.
Room thermostat calls
for second stage?
Yes
Y2 terminal on AHC
configured as input
passes signal from room
thermostat to outdoor unit.
NOTE - The outdoor unit
control directly controls the
outdoor unit operation.
Still calling for
second stage?
CBX40UHV
Room thermostat calls
for first
stage?
Yes
Y2 terminal is an
is
input to the AHC.
and
The indoor blower
will be controlled
according to the
jumper pin
selections.
Yes
No
Figure 39. Cooling Operation
CBX40UHV JUMP AND LINK GUIDE FOR FURTHER DETAILS.
Yes
No De-energize Y2 terminal on AHC.
Indoor blower speed will reset to
Y1 demand.
NOTE - The outdoor unit control
directly controls the outdoor unit
operation.
De-energize Y1 (and O in cooling) terminals on
AHC.
NOTE - The outdoor unit control directly
controls the outdoor unit operation.
De-energize indoor blower per ramping
Page 49
CUT ON-BOARD LINK Y1-Y2 FOR
TWO-STAGE A/C
IMPORTANT - USE CARE WHEN CUTTING LINKS TO
PREVENT DAMAGE TO CONTROL. SEE FIGURE 11,
Still calling for first
stage?
No
profile.
Y1-Y2
2-STAGE
COMPR
R-O
HEAT
PUMP
R-DS
DEHUM
OR
HARMONY
Yes