C7046A,B,C,D
Air Temperature Sensors
INSTALLATION INSTRUCTIONS
APPLICATION
2 (51)
8 (203)
1 (25)
1
1/16 (2)
The C7046 series of Air Temperature Sensors function
as primary and/or secondary sensors in electronic control
systems.
PLASTIC
BUSHING
3/4 (19)
1
(25)
LOCKING PUSH
NUTS (2)
1/4 (6)
DIAMETER (2 HOLES)
NEOPRENE
GASKET
INSTALLATION
5/16 (9) DIAMETER
(BUSHING)
M22402A
1
INSERTION LENGTH DEPENDS UPON THE MODEL.
When Installing this Product...
1. Read these instructions carefully. Failure to follow
them could damage the product or cause a hazard-
ous condition.
Fig. 1. C7046A,B,C,D Air Temperature
Sensor dimensions in in. (mm).
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.
NOTE: Sensor probe diameter is 1/4 in. (6 mm).
Location
The sensor should be located in the air duct or plenum
where it will sample an average air temperature. Avoid
locations where air stratification can cause sensing
errors.
CAUTION
Mounting
Electrical Shock or Equipment Damage
Hazard.
Mounting on Flat Duct or Plenum Surface (Fig. 2)
1. Cut a 3/8 in. (9.5 mm) hole in the duct or plenum
surface at the desired location.
Can shock individuals or short equipment
circuitry.
Disconnect power supply before installation.
2. Insert sensor probe into the duct or plenum until
the flange rests against the duct or plenum wall.
3. If necessary, use the flange as a template to mark
and drill two holes for No. 8 mounting screws.
4. Fasten the sensor to the duct or plenum surface
with two No. 8 sheet metal screws (not provided).
The sensor assembly (see Fig. 1) consists of an
aluminum sensor probe (element housed internally) with
attached flange that can be mounted on a flat duct or
plenum surface, or in a 2 in. by 4 in. (51 by 102 mm)
junction box using two No. 8 screws. Connections to the
sensor are made through two 6 in. (152 mm) leadwires.
Mounting in a Junction Box (Fig. 3)
1. Cut a 3/8 in. (9.5 mm) hole in the duct or plenum
surface at the desired location.
2. Remove the center rear knockout from the junction
box and insert the sensing probe through the
knockout with the flange flat against the outlet box.
3. Using the flange as a template, mark and drill two
holes in the junction box and the duct or plenum
surface for No. 8 mounting screws.
4. Insert sensor probe through both the junction box
knockout and the 3/8 in. (9.5 mm) hole drilled in the
duct or plenum and fasten the junction box and
sensor to the duct or plenum surface.
® U.S. Registered Trademark
Copyright © 2004 Honeywell International Inc. • All Rights Reserved
62-0216
C7046A,B,C,D AIR TEMPERATURE SENSORS
OPERATION AND CHECKOUT
W7081
LIMIT CONTROLLER
Operation
The C7046A,B,C Air Temperature Sensors consist of a
thermistor sensing element mounted in a tubular probe.
They are applied at various locations throughout single
zone and multizone duct systems. The negative
temperature coefficient (NTC) characteristic of the
thermistor element causes its resistance to decrease as
the sampled air temperature increases. This resistance
shift is balanced with other system sensor signals by
appropriate system logic panels to stabilize system
control.
ECONOMIZER/MIXED AIR LOW LIMIT–A5
1
2
3
4
5
6
C7046B
(OR C7100B)
MIXED AIR
SENSOR
50
60 NO JUMPER
55
COLD DECK LOW LIMIT–A6
1
2
3
4
5
6
C7046B
(OR C7100B)
COLD DECK
SENSOR
45
55 NO JUMPER
55
HOT DECK HIGH LIMIT–A7
1
2
3
4
5
6
C7046B
(OR C7100B)
HOT DECK
SENSOR
The C7046D Air Temperature Sensor consists of a
platinum thin film sensor element mounted in a tubular
probe. It can be applied at various locations throughout
single zone and multizone duct systems. The positive
temperature coefficient (PTC) characteristics of the
platinum thin film element causes its resistance to
increase as the sampled air temperature increases. This
resistance shift is balanced with other system sensor
signals by the Excel 500 Control System.
90
110
130 NO JUMPER
24 Vdc
7
8
–
+
+24 VDC
C7046B
C7046B
(OR C7100B)
REMOTE
RETURN
AIR SENSOR
(IF USED)
T7080A,B
Checkout
(OR C7100B)
ZONE (N)
DISCHARGE
SENSOR
Allow the C7046 Air Temperature Sensor to soak in the
air moving through the duct or plenum for a minimum of
five minutes before taking a resistance measurement.
1. Disconnect the sensor leadwires from the associ-
ated system components.
7
6
1
2
1
2
C7100B AVERAGING
TEMPERATURE SENSOR
MAY BE SUBSTITUTED IF
SPACE PERMITS.
5
4
3
8
2
2. Connect an ohmmeter across the leadwires.
3. Assure nominal resistance measurements are in
accordance with the resistance/temperature curves
shown in Figs. 7, 8 and 9.
4. Reconnect sensor leadwires to associated system
components.
REMOTE RETURN AIR
SENSOR USED WITH T7080B ONLY.
M17966A
Fig. 5. Connecting C7046B Air Temperature Sensor
for mixed air, cold deck and hot deck sensing, zone
discharge and optional remote return air sensing
in W7080 Multizone System.
5. Check operation of the complete control system.
17000
16000
15000
14000
13000
12000
11000
10000
9000
C7046D
XF521A/XF526
1
2
1
2
1
2
AI 1
AI 2
AI 3
3
4
5
6
7
8
8000
AI 4
AI 5
AI 6
AI 7
AI 8
9
7000
10
11
12
13
14
15
16
17
18
6000
5000
4000
3000
2000
1000
3,000 OHMS
AT 77 F (25 C)
10
-10
20
30
40
50
10
60
15
70
20
80
25
90
30
100
35
F
-5
0
5
C
TEMPERATURE (DEGREES)
M17969
M2825
Fig. 7. C7046A,C Sensor resistance vs. temperature.
Fig. 6. Connecting C7046D Air Temperature
Sensor to Excel 500 Control System.
3
62-0216
C7046A,B,C,D AIR TEMPERATURE SENSORS
120000
100000
RESISTANCE
(OHMS)
1159
22,800 OHMS AT
77 F (25 C)
80000
60000
40000
1141
20000
0
1126
1111
1096
1081
1066
1051
F
20
30 40 50 60 70 80 90 100 110 120 130 140
C
-7
0
5
10 15 20 25 30 35 40 45 50 55 60
M17973
TEMPERATURE (DEGREES)
1097 OHMS AT
77 F [25 C]
Fig. 8. C7046B Sensor resistance vs. temperature.
55
13
60
65
70
75
80
85
90
95
35
100 105 F
15
20
25
30
38
41 C
M2826
TEMPERATURE (DEGREES)
Fig. 9. C7046D Sensor resistance vs. temperature.
Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
Honeywell Limited-Honeywell Limitée
35 Dynamic Drive
Scarborough, Ontario
M1V 4Z9
62-0216 B.B. 11-04
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