Honeywell AT150F, AT175F Installation Instructions Manual
AT150F, AT175F
Universal Circuit Breaker T ransformers
INSTALLATION INSTRUCTIONS
APPLICA TION
These transformers provide power to 24 Vac circuits in heating/cooling control systems. Although the transformers are
typically used in heating/cooling control systems, they can be used in any application that does not exceed the load
ratings. They include a button for manually resetting the circuit breaker. They meet National Electrical Code Class 2 “not
wet” and Class 3 “wet” requirements and are Underwriters Laboratories (UL) Inc. listed under UL 1585. Transformers can
be foot-mounted or conduit/panel mounted. See Table 1 for additional specifications.
Table 1. Model Specifications.
Primary Secondary
Voltage
Model
Number
AT150F 120/208/240 9 in. leadwires 27.0 24.0 9 in. leadwires 50 VA
AT175F 120/208/240 9 in. leadwires 27.0 24.0 9 in. leadwires 75 VA
Input Voltage
(60 Hz)
208/277/480
208/277/480
Wiring
Connections
Open
Circuit
At Rated Power
Output
Wiring
Connections
INST ALLATION
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 beginning
installation to prevent electrical shock or equipment
damage.
The transformer can be foot-mounted or conduit/panel
mounted.
USE SCREWS OR
BOLTS THROUGH
SLOTS (4) IN
MOUNTING FEET
LEADWIRES
FOR PRIMARY
AND SECONDARY
CONNECTIONS
Output Rating
at 100 Percent
Power Factor
RESET
BUTTON
Mounting
Foot Mounting
Mount the transformer using screws (not included) through
the four 3/16 in. x 3/8 in. holes in the mounting feet. See
Fig. 1. Make line voltage primary connections within an
approved enclosure.
® U.S. Registered Trademark
Copyright © 1996 Honeywell Inc. • All Rights Reserved
X-XX UL
MOUNTING
FOOT (2)
Fig. 1. Foot mounting.
M6905
69-1014-1
AT150F, AT175F UNVIVERSAL CIRCUIT BREAKER TRANSFORMERS
Conduit/Panel Mounting
Mount the transformer on a plate or panel (not included)
with a 7/8 in. knockout. The transformer has a 1/2-14
NPSM conduit connector and lock nut.
1. With the conduit connector side of the transformer
facing the plate, thread the leadwires through the
plate knockout.
2. Insert the connector in the knockout.
3. While holding the plate in place, assemble and
tighten the lock nut to fasten the transformer
securely. See Fig. 2. Avoid damaging the leadwires
with the screwdriver.
4. Make line voltage primary connections within an
approved enclosure.
MOUNTING
PLATE (NOT
INCLUDED)
LEADWIRES
FOR PRIMARY
AND SECONDARY
CONNECTIONS
CONDUIT
CONNECTOR
LOCK NUT
END
BELL
RESET
BUTTON
M6906
Fig. 2. Conduit/panel mounting (plate not included).
Wiring
1. All wiring must comply with local codes and ordinances. Disconnect power before making wiring
connections to prevent electrical shock or equipment
damage.
2. Make the primary connections to the line voltage
power supply. Be sure to use the correct leadwires
for the available power supply. See Fig. 3.
3. Insulate the ends of the unused leadwires using wire
nuts or capping with a solderless connector.
4. Make the secondary connections to the 24 Vac
control circuit.
120/208/240 VAC MODELS
COMMON
PRIMARY
PRIMARY
1 SECONDARY LEADWIRES ARE BLUE AND YELLOW LEADWIRES.
BLACK IS COMMON WITH RESPECT TO THE TRANSFORMER
2
WINDING ONLY AND NOT THE EXTERNAL CIRCUIT.
120V
208V
240V
208/277/480 VAC MODELS
COMMON
208V
277V
480V
BLACK
WHITE
RED
ORANGE
BLACK
RED
BROWN
BLACK/RED
2
SECONDARY
1
2
SECONDARY
1
M6907
Fig. 3. Transformer schematics.
CHECKOUT
V oltage Check
After the installation is complete, turn on the power supply
and perform a voltage check.
1. Place the controlled equipment in operation and
observe through one complete cycle.
2. Using a voltmeter, verify the proper primary and
secondary voltages.
3. If the voltage readings are incorrect, make sure the
primary voltage connections are made properly.
4. Measure the voltage again.
a. If the proper primary voltage is measured and
the secondary voltage is significantly less than
the voltage shown in Table 1, the transformer
winding is damaged. Replace the transformer
and repeat the checkout procedures.
b. If the primary voltage is 0V, make sure the
power supply is connected properly or repair if
necessary. Repeat the checkout procedures.
5. Do not put the system into operation unless the
correct primary and secondary voltages are
measured.
Circuit Breaker
Overloading the transformer results in tripping the circuit
breaker. If the secondary side of the transformer is short
circuited, the circuit breaker trips in less than one minute.
Reset the circuit breaker by pressing the reset button on
the side of the transformer. It can take up to one hour for
the transformer to cool, allowing it to reset. If the circuit
breaker continues to trip, thoroughly check the system for
short circuits and the current draw.
Home and Building Control
Honeywell Inc.
Honeywell Plaza
P.O. Box 524
Minneapolis, MN 55408-0524
69-1014—1 C.H. Rev. 9-96 Printed in China
69-1014
Home and Building Control
Honeywell Limited-Honeywell Limitée
155 Gordon Baker Road
North York, Ontario
M2H 2C9
Helping You Control Your World®
2
Loading...