Honeywell PRESTIGE THX9321 - Manual (Page 136)

THX9321 PRESTIGE ® 2.0 AND THX9421 PRESTIGE ® IAQ WITH EIM
68-0311—02 136
* 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 K terminal in place of the Y and G terminals on conven-
tional 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.
CAUTION
Electrical Hazard.
Can cause electrical shock or equipment damage.
Disconnect power before wiring.
All wiring must comply with local electrical codes and
ordinances. See Fig. 319–327.
1. Select wiring diagram that corresponds with system type
and the equipment being installed (using the EIM or wir-
ing the thermostat directly to the HVAC equipment).
2. Loosen the screws for the appropriate terminals. Insert
wires in the terminal block under the loosened screw.
See Fig. 317.
3. Securely tighten each screw.
4. Push excess wire back into the hole.
5. Plug the hole with nonflammable insulation to prevent
drafts from affecting the thermostat.
6. See Fig. 319–327 for typical wiring hookups.
Table 14. THX9321 Terminal Designation Descriptions.
Conventional System Heat Pump
Terminal Description Terminal Description
C Common wire from secondary side of cooling
transformer (if 2 transformers).
C Common wire from secondary side of cooling
transformer.
Rc* Cooling power Rc* Cooling power
R* Heating power R Heating power
W Heat Stage 1 O/B Changeover valve for heat pumps
W2 Heat Stage 2 AUX-E Backup Heat/Emergency Heat
Y Compressor Stage 1 Y Compressor Stage 1
Y2 Compressor Stage 2 Y2 Compressor Stage 2
G Fan Relay G Fan Relay
A Connect to Economizer Module or Lighting Panel
(TOD).
L/A Connect to Compressor Monitor, Zone Panel,
Economizer Module or Lighting Panel (TOD).
U1 / U1
U2 / U2
Universal relay for humidification, dehumidification,
ventilation, or a stage of heating/cooling.
U1/ U1
U2 / U2
Universal relay for humidification, dehumidification,
ventilation, or a stage of heating/cooling.
K † Connect to K on Wire Saver module.
K † Connect to K on Wire Saver module.