Honeywell C7089 User Manual

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C7089 OUTDOOR SENSOR
3
69-1709EFS
OPERATION
Once installed and the Thermostat Installer Setup 
Number 0340 is set to 1 or 2, the outside temperature 
can be displayed on the thermostat. See Fig. 3.
Fig. 3. Outside temperature reading on 
TH8000 Series Thermostat.
The C7089 Outdoor Sensor converts outdoor ambient 
temperature to a resistance that the thermostat can 
interpret. 
The C7089 has a negative temperature coefficient (TC), which 
means that resistance decreases as 
the temperature increases. See Table 1.
CHECKOUT
Allow C7089B Outdoor Sensor to absorb outdoor air for a 
minimum of twenty minutes before taking a reading.
With an accurate thermometer (±1°F [0.5°C]) measure 
the temperature at the sensor location, allowing time for 
the thermometer to stabilize before reading.
To verify sensor resistance, remove one wire from one of 
the C7089 60-in. leadwires. Use an ohmmeter to 
measure the resistance across the sensor. Then verify 
the sensor accuracy with the temperature/resistance in 
Table 1.
CALIBRATION
The C7089 Outdoor Sensor is calibrated at the factory and can-
not be recalibrated in the field.
Heat On
SCHED
HOLD
CLOCK SCREEN
MORE
MON
TUE
WED
THU
FRI
SAT
AAT
SUN
AM
FAN
AUTO
SYSTEM
HEAT
Following
Schedule
Outside
Set To
M19971
Table 1. Sensor Resistance 
at Outdoor Temperature .
Outdoor Temperature
Ohms of 
Resistance
°F
°C
-20
-28.9
106926
-18
-27.8
100923
-16
-26.7
95310
-14
-25.6
90058
-12
-24.4
85124
-10
-23.3
80485
-8
-22.2
76137
-6
-21.1
72060
-4
-20.0
68237
-2
-18.9
64631
0
-17.8
61246
2
-16.7
58066
4
-15.6
55077
6
-14.4
53358
8
-13.3
49598