Honeywell C7089B User manual

X-XX UL
INSTALLATION INSTRUCTIONS
®U.S. Registered Trademark • All Rights Reserved
C7089B
Outdoor Sensor
APPLICATION
The C7089B Outdoor Sensor is used with the T8500 and
T8600 Thermostat families on models with outdoor
temperature option. It senses the outdoor temperature
for display at the touch of a key. The sensor is encapsu-
lated to protect against water and contaminants, and
includes 60 in. leadwires.
SPECIFICATIONS
Operating Ambient Temperature Range:
-40 to 128°F (-40 to 53°C)
Operating Relative Humidity:
5% to 95% non-condensing
Dimensions in inches (millimeters):
2-1/4 (57) x 3/8 (10) with 60 (1524) leadwires
INSTALLATION
When Installing this Product…
1. Read these instructions carefully. Failure to follow
them could damage the product or cause a
hazardous condition.
2. Check the ratings given in the instructions and on
the product to make sure the product is suitable for
your application.
3. Installer must be a trained, experienced service
technician.
4. After installation is complete, check out product
operation as provided in these instructions.
CAUTION
Disconnect power supply before connecting wiring
to prevent electrical shock or equipment damage.
Location and Mounting (Fig. 1)
Mount the sensor where:
•setting can not be tampered with.
•there is good air circulation.
•it can measure the true outdoor ambient temperature.
•surface is flat.
•he wire distance between the C7089 and thermostat
is less than 200 feet.
Do
not mount the sensor:
•in the direct sunlight.
•where hot or cold air blows on the sensor. Discharge
line from an outdoor compressor unit, vent or fan will
cause inaccurate temperature readings.
•where snow, ice or debris can cover it.
Use the following steps to mount the sensor.
1. Remove the sensor from the mounting clip.
2. Mark the area on the surface where the C7089B
mounting clip will be mounted.
3. Mount the clip.
69-1020-2

69-1020—2 2
C7089B OUTDOOR SENSOR
Fig. 1. Typical locations for outdoor sensor.
Wiring
CAUTION
Keep wiring at least one foot away from large
inductive loads such as motors, line starters,
lighting ballasts, and large power distribution
panels. Failure to follow these wiring practices
can introduce electrical interference (noise),
which can cause erratic system operation. Use
shielded cable to reduce interference when
rerouting is not possible.
IMPORTANT
Erratic temperature readings from a sensor can
occur as a result of any of the wiring practices
described below. These practices must be
avoided to assure proper operation. Use
shielded cable to reduce interference if rerout-
ing of sensor wiring is not possible.
a. Do not route temperature sensor wiring
with building power wiring, next to control
contactors or near light dimming circuits,
electric motors or welding equipment.
b. Avoid poor wiring connections.
c. Avoid intermittent or missing building earth
ground.
CAUTION
Disconnect the power supply before connecting
the wiring to prevent electrical shock or equip-
ment damage.
M7514
Fig. 2. Wiring diagram for the C7089B
Outdoor Sensor to the thermostat.
OPERATION
The C7089B Outdoor Sensor converts outdoor ambient
temperature to a resistance that the thermostat can
interpret. The outdoor temperature is displayed when the
Information key is pressed.
NOTE: The thermostat Installer Setup mode number 24
must be set to 01 for the outdoor temperature to be
displayed.
The C7089B has a negative temperature coefficient
(TC), which means that the resistance increases as the
temperature decreases. Fig. 3 shows the resistance
characteristics of the C7089B Sensor.
1
2
3
2
1
USE APPROPRIATE MOUNTING MEANS FOR THE TYPE
OF STRUCTURE.
PLUG WIRING HOLE WITH NON-HARDENING CAULK OR PUTTY.
OT TERMINAL LOCATION VARIES WITH MODEL.
C7089
WIRING HOLE
THROUGH
STRUCTURE
WY
OGR
BC
OT OT
T8600 SUBBASE
M10165
3
Wiring must comply with applicable codes, ordinances and
regulations.
1. Wire the C7089B Outdoor Sensor to the OT
terminals on the thermostat. If the leadwire
provided with the C7089B is not long enough, run
cable to a hole at the selected C7089B location.
Color-coded, 18-gauge thermostat wire is recom-
mended. For an example of general wiring of the
C7089B, see Fig. 2. Pigtail wiring can be used.
2. Mount the C7089B in its mounting clip.
3. Plug wiring hole using nonhardening caulk or putty.

69-1020—2
3
C7089B OUTDOOR SENSOR
Fig. 3. C7089B sensor resistance vs. temperature
performance characteristics.
CHECKOUT
Allow the C7089B Outdoor Sensor to soak in the outdoor air
for a minimum of five 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. Press the
Information key on the thermostat until the display shows
Outdoor followed by the temperature reading. See Fig. 4. The
reading should match the reading taken outdoors.
To verify the resistance of the sensor, remove one wire from
one of the C7089B wiring terminals. Use an ohmmeter to
measure the resistance across the sensor. Then verify sensor
accuracy with the temperature/resistance curve of Fig. 3.
Fig. 4. Outdoor temperature display
on the thermostat.
CALIBRATION
The C7089B Outdoor Sensor is calibrated at the factory
and cannot be recalibrated at the field.
0
100
200
300
400
500
600
700
800
900
RESISTANCE (K ohm)
-40
(-40)
-20
(-29)
0
(-18) 20
(-7) 40
(4)
60
(16) 80
(27)
100
(38)
120
(49)
°F
(°C)
OUTDOOR TEMPERATURE
M10172A
T8600
M13284
Outdoor

69-1020—2 4
C7089B OUTDOOR SENSOR
Honeywell Limited-Honeywell Limitée
35 Dynamic Drive
Scarborough, Ontario M1V 4Z9
69-1020—2 J.H. Rev. 11-98
Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422