System Installation Guide
12
69-2490—05
EIM wiring guide — geothermal radiant heat
Typical wiring for geothermal radiant heat, geothermal forced-air, and backup
heat with one transformer. See page 19 for operation.
1
2
3
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).
“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.
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.
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
3
3
2
1
SENSORS
AIR HANDLER
TRANSFORMER
STATUS
LEDS
JUMPERS
OPTIONAL
JUMPER
POWER
HEAT
COOL
FAN
U1
U2
U3
TO THERMOSTAT
HEAT PUMP
EIM
2
CONNECT OPTIONAL
SENSORS TO
S1 AND S2 TERMINALS
(MAX. 2 SENSORS)
MCR32947A
