Terminal Designations - Honeywell visionpro series Installation Manual

1.4 Wire the thermostat.
Once wiring is complete turn on 24vac.
Conventional System
Terminal
Common wire from secondary side of
C
cooling transformer (if 2 transformers).
Rc* Cooling power.
R* Heating power.
W Heat Stage 1
W2 Heat Stage 2
Y Compressor Stage 1
Y2 Compressor Stage 2
G Fan Relay
Connect to Economizer Module or
A
Lighting Panel (TOD).
Universal relay for humidification,
U1 / U1 dehumidification, ventilation, or a stage of
heating/cooling.
Universal input for a wired indoor, outdoor
S1 / S1
or discharge sensor.
K** Connect to K on Wire Saver module.
*
Remove factory installed jumper for two transformer systems.
**
The THP9045A1023 Wire Saver module is used on heat/cool systems when you only have four wires at the thermostat and you
would like the thermostat to be powered with a common wire. Use the
or heat pump systems to provide control of the fan and the compressor through a single wire—the unused wire then becomes your
common wire. See THP9045 instructions for more information.

Terminal Designations

Description
C
K
RC
R
U1
U1
U2
U2
Terminal
Common wire from secondary side of
C
cooling transformer.
Rc Cooling power.
R Heating power.
O/B Changeover valve for heat pumps.
AUX-E Backup Heat/Emergency Heat
Y Compressor Stage 1
Y2 Compressor Stage 2
G Fan Relay
Connect to Compressor Monitor, Zone
L/A Panel, Economizer Module or Lighting
Panel (TOD).
Universal relay for humidification,
U1 / U1 dehumidification, ventilation, or a stage of
heating/cooling.
Universal input for a wired indoor, outdoor
S1 / S1
or discharge sensor.
K** Connect to K on Wire Saver module.
K terminal in place of the Y and G terminals on conventional
4
CONVENTIONAL
S1
S1
W
Y
G
W2
Y2
A
HEAT PUMP
Heat Pump
Description
S1
S1
O/B
Y
G
AUX
-E
Y2
L/A