Honeywell PRESTIGE THX9321 - Manual (Page 140)

THX9321 PRESTIGE ® 2.0 AND THX9421 PRESTIGE ® IAQ WITH EIM
68-0311—02 140
Typical wiring for geothermal radiant heat, geothermal forced-air, and backup heat with one transformer.
Fig. 321. EIM wiring guide — geothermal radiant heat.
1 U1, U2 or U3 terminals must be used for geothermal radiant heat (ISU 2010). Thermostat allows 2 stages of radiant heat—geo-
thermal (stage 1) and boiler (stage 2).
2 “U” terminals are normally open dry contacts when set up for geothermal radiant heat. You must install a field jumper if radiant
heat is powered by system transformer. Do NOT install a field jumper if radiant heat has its own transformer.
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 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.
5 Connect wireless adapter to ABCD for extended wireless range.
NOTE: For setup and operation, see “Geothermal Radiant Heat” beginning on page 100.
O/B
AUX1
AUX2
O/B
R
C
AUX1
AUX2
G
L
Y2
Y
L/A
CHANGEOVER VALVE
BACKUP HEAT
STAGE 1
FAN RELAY
120
VAC
24
VAC
COMPRESSOR
STAGE 1
COMPRESSOR
STAGE 2
BACKUP HEAT
STAGE 2
COMPRESSOR MONITOR
OR ZONE PANEL
GEOTHERMAL RADIANT
HEAT STAGE 1
AIR HANDLER
TRANSFORMER
STATUS
LEDS
JUMPERS
OPTIONAL
JUMPER
POWER
HEAT
COOL
FAN
U1
U2
U3
TO THERMOSTAT
HEAT PUMP
EIM
3
1
3
S4
S4
S3
S3
CONNECT OPTIONAL
SENSORS TO
S3 AND S4 TERMINALS
A
B
C
D
4
SENSORS
2
CONNECT OPTIONAL
SENSORS TO
S1 AND S2 TERMINALS
4
2
5