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Cooling Operation
Room thermostat
calls for first
stage?
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.
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?
Still calling for first
stage?
Y2 terminal on AHC is
configured as input and passes
signal from room thermostat to
outdoor unit.
Y2 terminal is an
input to the AHC.
The indoor blower
will be controlled
according to the
jumper pin
selections.
Still calling for second
stage?
NOTE − The outdoor unit control directly
controls the outdoor unit operation.
De−energize Y1 (and O in cooling) terminal
on AHC.
De−energize indoor blower per ramping
profile.
No
Yes
AHC on−board link must be cut between Y1 and Y2 to allow 2 stage
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
NOTE − The outdoor unit control directly controls the outdoor
unit operation.
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.
NOTE − The outdoor unit
control directly controls the
outdoor unit operation.
Yes
Yes
Yes
Yes
No
No
CUT ON−BOARD LINK Y1−Y2 FOR
TWO−STAGE A/C
Y1−Y2
2−STAGE
COMPR
R−O
HEAT
PUMP
R−DS
DEHUM
OR
HARMONY
C
U
T
FOR OPTION
RECOMMEND
USE FIGURE 21 AS A REFERENCE FOR SETTING
JUMPER CONFIGURATIONS ON THE AIR HANDLER CONTROL.
IMPORTANT
− Use care when cutting links to prevent damage to
control. See figure 21, CBX32MV jump and link guide for further
details.
