Honeywell VisionPRO 8000 Product Data page 36

TM
VisionPRO 8000 Touchscreen Programmable Thermostat
C7089U Outdoor Temperature Sensor
Operation
When installed with Thermostat Installer Setup Number 0340
set to 1 or 2, the outside temperature can be displayed on the
thermostat. See Fig. 35.
MON TUE WED
FAN
Inside
AUTO
SYSTEM
HEAT
SCHED HOLD
Fig. 35. 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 12.
Checkout
Allow C7089U 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 12.
Calibration
The C7089 Outdoor Sensor is calibrated at the factory and
cannot be recalibrated in the field.
68-0280—01
THU FRI SAT A A T SUN
Set To
Following
Schedule
Outside
AM
CLOCK SCREEN MORE
M22453
Table 12. Sensor Resistance at Outdoor Temperature.
Outdoor
Ohms of
Temperature
°F °C
-20 -28.9
-18 -27.8
-16 -26.7
-14 -25.6
-12 -24.4
-10 -23.3
-8 -22.2
-6 -21.1
-4 -20.0
-2 -18.9
0 -17.8
2 -16.7
4 -15.6
6 -14.4
8 -13.3
10 -12.2
12 -11.1
14 -10.0
16 -8.9
18 -7.8
20 -6.7
22 -5.6
24 -4.4
26 -3.3
28 -2.2
30 -1.1
32 0.0
34 1.1
36 2.2
38 3.3
40 4.4
42 5.6
44 6.7
46 7.8
48 8.9
50 10.0
36
Outdoor
Temperature
Resis-
tance °F °C
106926 52 11.1
100923 54 12.2
95310 56 13.3
90058 58 14.4
85124 60 15.6
80485 62 16.7
76137 64 17.8
72060 66 18.9
68237 68 20.0
64631 70 21.1
61246 72 22.2
58066 74 23.3
55077 76 24.4
53358 78 25.6
49598 80 26.7
47092 82 27.8
44732 84 28.9
42506 86 30.0
40394 88 31.1
38400 90 32.2
36519 92 33.3
34743 94 34.4
33063 96 35.6
31475 98 36.7
29975 100 37.8
28558 102 38.9
27219 104 40.0
25949 106 41.1
24749 108 42.2
23613 110 43.3
22537 112 44.4
21516 114 45.6
20546 116 46.7
19626 118 47.8
18754 120 48.9
17926 —
Ohms of
Resis-
tance
17136
16387
15675
14999
14356
13743
13161
12607
12081
11578
11100
10644
10210
9795
9398
9020
8659
8315
7986
7672
7372
7086
6813
6551
6301
6062
5834
5614
5404
5203
5010
4826
4649
4479
4317