Honeywell C7046A User Manual

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Air Temperature Sensors

INSTALLATION INSTRUCTIONS

APPLICATION

The C7046 series of Air Temperature Sensors function
as primary and/or secondary sensors in electronic control
systems.

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

Electrical Shock or Equipment Damage
Hazard.
Can shock individuals or short equipment
circuitry.

Disconnect power supply before installation.

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.

2 (51

/4 (19

5/16 (9) DIAMETE

(BUSHING

INSERTION LENGTH DEPENDS UPON THE MODEL.

1

Fig. 1. C7046A,B,C,D Air Temperature

Sensor dimensions in in. (mm).

8 (203

PLASTI

BUSHIN

LOCKING P

NUTS (2

1/4 (6

IAMETER (2 HOLES

1/16 (2

NEOPRENE

M22402

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.

Mounting

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.

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).

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

SENSO

OBE

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S

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O

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SYSTEM

COMPO

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CO

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S

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A

SENSO

E

SYS

DUCT O

UM

GE

S

Y

CONDU

OX

CONNECTOR

CONDUIT

E

(

)

SYS

COMPO

S

CO

S

W

)

A

S

)

R

PR

T
APPROPRIAT

NENT

M22403

Fig. 2. Mounting C7046 Air Temperature
Sensor on a flat duct or plenum surface.

TANDARD UTILIT

IT B

LOCKNUT

TO APPROPRIATE

TEM

NENT

TEM

R

PLEN

Fig. 3. Mounting C7046 Air Temperature

Sensor in a junction box.

FLAN

R

PROB

NNECT SENSOR WIRE

ITH TWO WIRENUT

CONNECTORS (NOT PROVIDED

Wiring

CAUTION

Electrical Shock or Equipment Damage
Hazard.
Can shock individuals or short equipment
circuitry.

Disconnect power supply before installation.

SYSTEM DUCT
OR PLENUM

NO. 8 (4mm
MOUNTING SCREW

NOT PROVIDED

FLAN

NNECT SENSOR
WIRES WITH TW
WIRENUT CONNECTOR

NOT PROVIDED

NO. 8 (4 mm)
MOUNTING

CREWS (NOT

PROVIDED

FACEPLAT

OPTIONAL

M22404

CAUTION

Erratic System Operation Hazard.
Failure to follow proper wiring practices can
introduce disruptive electrical interference
(noise).

Keep wiring at least one foot away from large

inductive loads such as motors line starters,
lighting ballasts, and large power distribution
panels.

Shielded cable is required in installations where

these guidelines cannot be met.

Ground shield only to grounded controller case.

IMPORTANT

1. All wiring must agree with applicable codes,
ordinances and regulations.

2. Do not mount sensor in incorrect environment.

3. Wire according to the applicable controller
instructions.

4. Erratic temperature readings from a sensor can
be caused by improper wiring practices. These
must be avoided to assure proper operation:

•Avoid poor wiring connections.

•Avoid intermittent or missing building earth

ground.

•Do not mount sensor in incorrect environment.

Connect low voltage wiring from the sensor to the
appropriate system component terminals using
solderless connectors. See Fig. 3.

NOTES:

1. For connections to the W973 Single Zone

Logic Panel, see Fig. 4.

2. For connections to the W7080 Multizone

System, see Fig. 5.

3. For connections to the Excel 500 Control

System, see Fig. 6.

4. For additional wiring information, refer to the

appropriate specification.

W973 LOGIC PANEL

SENSOR STAT 24 VAC ECONO

C +20 H N

TT134251TRTRWBY

C7046A

1

POWER SUPPLY. PROVIDE DISCONNECT
MEANS AND OVERLOAD PROTECTION
AS REQUIRED.

Fig. 4. Connecting C7046A Air Temperature
Sensor to a W973 Single Zone Logic Panel.

1

L1

L2

(HOT)

R

M17965

62-0216 2

A

W7081

LIMIT CONTROLLER

ECONOMIZER/MIXED AIR LOW LIMIT–A5

21

3456

50

55

COLD DECK LOW LIMIT–A6

21

HOT DECK HIGH LIMIT–A7

21

12C7100B AVERAGING

TEMPERATURE SENSOR
MAY BE SUBSTITUTED IF
SPACE PERMITS.

REMOTE RETURN AIR
SENSOR USED WITH T7080B ONLY.

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.

C7046D XF521A/XF526

1

2

Fig. 6. Connecting C7046D Air Temperature

Sensor to Excel 500 Control System.

60 NO JUMPER

3456

45

55

55 NO JUMPER

3456

90

110

130 NO JUMPER

24 Vdc

78

–+

+24 VDC

C7046B

(OR C7100B)

REMOTE
RETURN

AIR SENSOR

(IF USED)

1

2

T7080A,B

7

6

5

4

2

1

AI 1

2

3

AI 2

4

5

AI 3

6

7

8

AI 4

9

10

AI 5

11

12

AI 6

13

14

AI 7

15

16

AI 8

17

18

1

2

3

8

(OR C7100B)

MIXED AIR

SENSOR

(OR C7100B)

COLD DECK

SENSOR

(OR C7100B)

HOT DECK

SENSOR

C7046B
(OR C7100B)
ZONE (N)
DISCHARGE
SENSOR

M2825

C7046B

C7046B

C7046B

M17966

C7046A,B,C,D AIR TEMPERATURE SENSORS

OPERATION AND CHECKOUT

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.

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.

Checkout

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 associ­ated system components.

2. Connect an ohmmeter across the leadwires.

3. Assure nominal resistance measurements are in

accordance with the resistance/temperatu re curves
shown in Figs. 7, 8 and 9.

4. Reconnect sensor leadwires to associated system
components.

5. Check operation of the complete control system.

17000

16000

15000

14000

13000

12000

11000

10000

9000

8000

7000

6000

RESISTANCE (OHMS)

5000

4000

3000

2000

1000

0-10

TEMPERATURE (DEGREES)

605040 70

5

15

Fig. 7. C7046A,C Sensor resistance vs. temperature.

2010

3,000 OHMS
AT 77 F (25 C)

8010 20 30 90 100

30 35

25-5

M17969

F

C

3 62-0216

C7046A,B,C,D AIR TEMPERATURE SENSORS

120000

100000

80000

60000

40000

20000

0

RESISTANCE (OHMS)

20

-7 50 60

50 70 90

30

40

0 10 20 30 40

5 15 25

22,800 OHMS AT
77 F (25 C)

60 80 100

TEMPERATURE (DEGREES)

35

110

120

45 55

130

M17973

Fig. 8. C7046B Sensor resistance vs. temperature.

RESISTANCE
(OHMS)
1159

1141

1126

F

140

C

1111

1096

1081

1066

1051

60 65 70 75 80 85 90 95 100 105

55

13 15

20

TEMPERATURE (DEGREES)

1097 OHMS AT
77 F [25 C]

25

30 35 38 41

M2826

F

C

Fig. 9. C7046D Sensor resistance vs. temperature.

Automation and Control Solutions

Honeywell International Inc. Honeywell Limited-Honeywell Limitée
1985 Douglas Drive North 35 Dynamic Drive
Golden Valley, MN 55422 Scarborough, Ontario

M1V 4Z9

62-0216 B.B. 11-04 www.honeywell.com