Honeywell PRESTIGE THX9321 System Installation Manual page 12

System Installation Guide
EIM wiring guide — geothermal radiant heat
Typical wiring for geothermal radiant heat, geothermal forced-air, and backup
heat with one transformer.
EIM
POWER
HEAT
COOL
STATUS
LEDS
OPTIONAL
JUMPER
1
U1, U2 or U3 terminals must be used for geothermal radiant heat (ISU 2010). Thermostat allows 2 stages of radiant heat—
geothermal (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 wiring section.
69-2490—03
69-2490_B.indd 12
TO THERMOSTAT
FAN
U1
U2
U3
2
JUMPERS
SENSORS
O/B
HEAT PUMP
O/B
AUX1
AUX1
AUX2
AUX2
L/A
3
COMPRESSOR MONITOR
OR ZONE PANEL
3
GEOTHERMAL RADIANT
HEAT STAGE 1
1
R
C
2
CONNECT OPTIONAL
S1 AND S2 TERMINALS
(MAX. 2 SENSORS)
12
CHANGEOVER VALVE
BACKUP HEAT
STAGE 1
BACKUP HEAT
STAGE 2
COMPRESSOR
Y
STAGE 1
COMPRESSOR
Y2
STAGE 2
G
FAN RELAY
L
AIR HANDLER
TRANSFORMER
24 120
VAC VAC
SENSORS TO
MCR32947
7/13/2011 1:41:55 PM