Comfort Stat CDT901 - Manual (Page 35)

CDT900 Series Touchscreen Programmable Thermostata
1. POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED
2. FACTORY INSTALLED JUMPER.
3
．
OUTDOOR SENSOR REQUIRED IN SYSTEM WITH FOSSIL FUEL BACKUP HEAT THAT IS NOT USING AN EXTERNAL FOSSIL FUEL KIT
4
．
OPTIONAL OUTDOOR OR INDOOR REMOTE SENSOR. AVAILABLE ON SELECT MODELS. WIRES MUST HAVE A CABLE SEPARATE FROM THE
THERMOSTAT CABLE
5
．
MUST CONNECT THE 24 VAC COMMON WHEN USING L. THE TERMINAL IS SHOWN AS EQUIPMENT MONITOR, CAN ALSO BE USED AS
A 24 VAC OUTPUT. SEE "HEAT PUMP LED" SECTION FOR MORE INFORMATION.
6
．"O/B" TERMINAL SET TO CONTROL AS EITHER "O" OR "B" IN THE INSTALLER SETUP.
Fig. 21. Typical hookup of multistage heat pump with auxiliary/backup heat (3H/2C heat
pump).
34
3 4
HEAT PUMP
S1 S2 C R RC W W2 Y2 Y G
S1 S2 C R RC E L Y2 Y G O/B AUX
OUTDOOR/INDOOR
TEMPERATURE
SENSOR
2
R C 1
CHANGEOVER
VALVE
FAN RELAY
OPTIONAL
24VAC
COMMON
CONNECTION
6
5
EMERGENCY
HEAT RELAY HEAT 2 RELAY
(AUXILIARY HEAT)
EQUIPMENT MONITOR
COMPRESSOR 1
COMPRESSOR 1