Eim Wiring Guide — Heat Pump Systems - Honeywell THX9321 Prestige 2.0 Product Data

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 sen-
sor, 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 151.
4 Connect wireless adapter to ABCD for extended wireless range.
EIM
POWER
HEAT
COOL
STATUS
FAN
LEDS
U1
U2
U3
A
B
4
C
D
S4
CONNECT OPTIONAL
S4
SENSORS TO
S3 AND S4 TERMINALS
S3
S3
Fig. 320. EIM wiring guide — heat pump systems.
®
THX9321 PRESTIGE 2.0 AND THX9421 PRESTIGE
TO THERMOSTAT
O/B
HEAT PUMP
O/B
AUX1
AUX1
AUX2
AUX2
L/A
3
1
SENSORS
139
®
CHANGEOVER VALVE
BACKUP HEAT
STAGE 1
BACKUP HEAT
STAGE 2
COMPRESSOR
Y
STAGE 1
Y2 COMPRESSOR
STAGE 2
G
FAN RELAY
L/A
COMPRESSOR
MONITOR OR
3
ZONE PANEL
JUMPERS
AIR HANDLER
TRANSFORMER
R
24 120
C
VAC VAC
CONNECT OPTIONAL
SENSORS TO
S1 AND S2 TERMINALS
2
IAQ WITH EIM
68-0311—02