INSTALLATION INSTRUCTIONS
69-0251-3
AT120A, AT140A, AT150A, AT175A
Universal Transformers
APPLICATION
These transformers are for use in 24 Vac nominal control
circuits. They are typically used in heating/cooling control
systems but can be used in any application that does not
exceed the load ratings. They meet National Electrical
Code Class 2 “not wet” and Class 3 “wet” requirements
and are Underwriters Laboratories (UL) Inc. listed under
UL 1585. They can be mounted through a 7/8 in. knock-
out on the accessory mounting plate (included), or with
the integral mounting feet. See Table 1 for additional
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
Electrical Hazard.
Can cause electrical shock or equipment
damage.
Disconnect power supply before beginning
installation.
Table 1. Model Specifications.
Model
Number
Primary
Secondary
Output Rating at
100 Percent Power
Factor
Input
Voltage
(60 Hz)
Wiring
Connections
Voltage
Wiring
connections
Open
Circuit
At Rated
Power
Output
AT120A
120/208/
240
9 in. leads
27.0
24.0
Screw
terminals
20 VA
AT140A
120
9 in. leads
27.0
24.0
Screw
terminals
40 VA
120/208/
240
120/240
208/240
AT150A
120/208/
240
9 in. leads
27.5
24.0
Screw
terminals
50 VA
AT175A
120/208/
240
9 in. leads
27.5
24.0
Screw
terminals
75 VA
