® U.S. Registered Trademark
Copyright © 1996 Honeywell Inc. • All Rights Reserved
X-XX UL
INSTALLATION INSTRUCTIONS
AT150F, AT175F
Universal Circuit Breaker Transformers
APPLICATION
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.
INSTALLATION
When Installing this Product…
1. Read these instructions carefully. Failure to follow
them could damage the product or cause a hazard-
ous 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.
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.
Fig. 1. Foot mounting.
P r i m a r y
Secondary
Voltage
Output Rating
Model
Number
Input Voltage
(60 Hz)
Wiring
Connections
Open
Circuit
At Rated Power
Output
Wiring
Connections
at 100 Percent
Power Factor
AT150F
120/208/240
9 in. leadwires
27.0
24.0
9 in. leadwires
50 VA
208/277/480
AT175F
120/208/240
9 in. leadwires
27.0
24.0
9 in. leadwires
75 VA
208/277/480
69-1014-1
USE SCREWS OR
BOLTS THROUGH
SLOTS (4) IN
MOUNTING FEET
RESET
BUTTON
MOUNTING
FOOT (2)
LEADWIRES
FOR PRIMARY
AND SECONDARY
CONNECTIONS
M6905
