System Installation Guide
10
69-2490—05
Typical wiring of a conventional system with up to 3-stage heat and 2-stage cool
with one transformer.
EIM wiring guide — conventional systems
See following pages for additional thermostat wiring guidelines for heat pumps,
geothermal systems and optional Economizer.
1
2
3
4
See guides on following pages for thermostat wiring and geothermal radiant heat wiring.
Wire a maximum of 2 sensors using the S1 and S2 terminals. See ISU 5000-6190 for options. S1 and S2 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.
Remove jumper(s) if using separate transformers.
See Economizer wiring section.
HEAT STAGE 1
HEAT STAGE 2
HEAT STAGE 3
FAN
TO THERMOSTAT
STATUS
LEDS
JUMPERS
SENSORS
CONV
FURNACE
R
C
W
W2
W3
G
Y2
Y
TRANSFORMER
120
VAC
24
VAC
COMPRESSOR
STAGE 1
COMPRESSOR
STAGE 2
POWER
HEAT
COOL
FAN
U1
U2
U3
A
CONNECT OPTIONAL
SENSORS TO
S1 AND S2 TERMINALS
(MAX. 2 SENSORS)
EIM
1
3
2
4
MCR32945A