Honeywell Home THX9321 Prestige 2.0 Manual page 138

®
THX9321 PRESTIGE 2.0 AND THX9421 PRESTIGE
Typical wiring of a heat pump system with up to four-stage heat and two-stage cool with one transformer.
2
1 See guides on following pages for thermostat wiring and geothermal radiant heat wiring.
2 Wire a maximum of 4 sensors using the S1-S4 terminals. S1-S4 terminals can be connected to an indoor sensor, outdoor
sensor, discharge sensor, return sensor, dry contact device to display an alert or an occupancy sensor for remote setback.
3 L/A terminal sends continuous output when thermostat is set to EM HEAT mode, except when set up for Economizer or
TOD. See "Economizer Module Wiring Diagrams" beginning on page 150.
4 Connect wireless adapter to ABCD for extended wireless range.
68-0311—08
®
IAQ WITH EIM
EIM
POWER
HEAT
COOL
STATUS
FAN
LEDS
U1
U2
U3
A
B
4
C
D
S4
CONNECT OPTIONAL
S4
SENSORS TO
S3
S3 AND S4 TERMINALS
S3
Fig. 325. EIM wiring guide — heat pump systems.
TO THERMOSTAT
O/B
CHANGEOVER VALVE
HEAT PUMP
O/B
AUX1
AUX1
AUX2
AUX2
Y
L/A
Y2
3
G
L/A
3
1
R
C
CONNECT OPTIONAL
SENSORS TO
SENSORS
S1 AND S2 TERMINALS
2
138
BACKUP HEAT
STAGE 1
BACKUP HEAT
STAGE 2
COMPRESSOR
STAGE 1
COMPRESSOR
STAGE 2
FAN RELAY
COMPRESSOR
MONITOR OR
ZONE PANEL
JUMPERS
AIR HANDLER
TRANSFORMER
24 120
VAC VAC