Install Instructions

ManualsBrandsResideo ManualsTransformersFoot mounted 120/208/240 Vac Transformer w/ 9 in. Lead Wires (75VA)

Table Of Contents

INSTALLATION INSTRUCTIONS

69-0251-04

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. knockout 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 haz-

ardous 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.

Mounting

The transformer can be mounted in one of three ways:

• foot mounting.

• plate mounting.

• mounting through outlet box knockout hole.

Foot Mounting

1. Mount the transformer using screws (not sup-

plied) through the four 3/16 in. x 3/8 in. holes in

the mounting feet.

2. Make line voltage primary connections within an

approved enclosure. See Fig. 1.

3. Discard the mounting plate.

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

Summary of content (4 pages)

PAGE 1
AT120A, AT140A, AT150A, AT175A Universal Transformers INSTALLATION INSTRUCTIONS 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. knockout on the accessory mounting plate (included), or with the integral mounting feet. See Table 1 for additional specifications. APPLICATION These transformers are for use in 24 Vac nominal control circuits.
PAGE 2
AT120A, AT140A, AT150A, AT175A UNIVERSAL TRANSFORMERS PLATE MOUNTED AT CLAMP ON PRIMARY END BELL MOUNTING PLATE SCREW TERMINALS FOR SECONDARY CONNECTIONS END BELL LEADWIRES FOR PRIMARY CONNECTIONS USE SCREWS OR BOLTS THROUGH SLOTS (4) IN MOUNTING FEET SCREW TERMINALS FOR SECONDARY CONNECTIONS LEADWIRES FOR PRIMARY CONNECTIONS CLAMP SCREW AND CLAMP 1 MOUNTING FOOT (2) RAISED PORTION OF LARGE CENTER KNOCKOUT M9161 PLATE MOUNTED AT THE LAMINATIONS Fig. 1. Foot mounting.
PAGE 3
AT120A, AT140A, AT150A, AT175A UNIVERSAL TRANSFORMERS WITH RAISED PORTION OF KNOCKOUTS FACING YOU: 1. PRY UP TOP SECTION OF LARGE KNOCKOUT BY INSERTING SCREWDRIVER FIRST AT ONE SIDE OF SLOT AND THEN AT THE OTHER SIDE. M12126 Fig. 3. When screw is tightened, clamp holds plate on transformer. MOUNTING PLATE AT LAMINATIONS 1. Remove the large rectangular knockout in the mounting plate as shown in Fig. 4. 2. Hold the transformer so the clamp on the end bell faces you. 3.
PAGE 4
AT120A, AT140A, AT150A, AT175A UNIVERSAL TRANSFORMERS Mounting Through Outlet Box Knockout The transformer can be mounted on an outlet box using the clamp on the primary end bell. The mounting plate is not used. To mount the transformer on an outlet box: 1. Turn the clamp screw almost all the way out. 2. From outside box, thread the primary leadwires through suitable 7/8 in. knockout. Fit the clamp and screw through the knockout. Do not mount the transformer through a plastic knockout. 3.