507746-01
Issue 1821
Page 33 of 39
Cooling Operation
Room thermostat
calls for first
stage?
Air Handler Control (AHC) receives inputs on Y1 terminal
.
Y1 terminal on air handler control is configured as input and
passes signal from room thermostat to outdoor unit.
Y1 input to the air handler control 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 air handler
control is configured as input
and passes signal from room
thermostat to outdoor unit.
Y2 terminal is an
input to the air
handler control. 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 air handler control.
De-energize indoor blower per ramping
profile.
No
Yes
Air handler control on-board link must be cut between Y1 and Y2 to allow
two-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 air handler
control. 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
CUT
FOR OPTIO
N
NOTE
— USE FIGURE 19 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 19, BCE7S jump and link guide, for further
details.
Figure 24.
