Heat Pump Operation; Air Handler Control Ahc) Indoor Blower Mode Speed/Profiles Settings; Single Or Two-Stage Unit - Lennox CBX40UHV Series Installation And Service Procedure

7. Heat Pump Operation

Air Handler Control AHC) Indoor Blower Mode Speed and Profiles settings
1. Set Cooling Mode Blower Speed jumper pin . (Low and high indoor blower CFM settings are
identical for cooling and heat pump)
2. Set Blower Adjust Selection jumper pin.
3. Set Cooling Mode Blower Ramping jumper pin (Cooling calls - All ramping profiles are
active) (Heating calls - Only ramping profiles 1 and 2 are active. If profiles 3 or 4 are se­
lected, AHC will default to profile 1)
A. Profile 1 does not provide any ramping profiles.
B. Profile 2 provides a 30 second indoor blower ON delay at the start of a heat pump
heating demand. (45 second indoor blower OFF delay)
4. Simultaneous Heat Pump and electric heat call: Indoor Blower will operate at the
highest CFM requested by the heat pump or the electric heat blower speed selection.

Single or Two-Stage Unit

1. AHC on-board link must be cut between Y1 and Y2 to allow two stage cooling operation.
2. AHC on-board link must be cut between R and O to allow heat pump 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 2
Yes
Y2 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.)
Still calling for 2
Heating
nd
stage?
Yes
Y2 terminal is an
input to the AHC.
The indoor blower
will be controlled
according to the
jumper pin
selections.
nd
stage?
No
Figure 38. Heat Pump Operation
Room thermostat calls for
st
stage?
1
Air Handler Control (AHC) receives inputs on Y1, and O
.
terminals .
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 mode blower speed , ramping and adjust
Yes
No
Yes
Page 48
CUT ON-BOARD LINK Y1-Y2
FOR TWO-STAGE A/C
CUT ON-BOARD LINK R -O.
IMPORTANT - USE CARE WHEN CUTTING LINKS TO
PREVENT DAMAGE TO CONTROL. SEE FIGURE 11,
CBX40UHV JUMP AND LINK GUIDE FOR FURTHER
DETAILS.
Cooling
selection jumper pins.
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.)
Still calling for 1
Stage?
No
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
profile.
Y1-Y2
2-STAGE
COMPR
R-O
HEAT
PUMP
R-DS
DEHUM
OR
HARMONY
Yes
st
CBX40UHV