Johnson Controls A25 Series - User Manual

FANs 125, 121
Product/Technical Bulletin A25
Issue Date 0316
© 2016 Johnson Controls, Inc.
1
Part 24-7664-656, Rev. A
Code No. LIT-125118
A25 Series Warm Air Control with Manual Reset
The A25 Series Warm Air Control with Manual Reset
is designed to shut down fans, burners, dampers, etc.,
when the temperature of the sensed air becomes
greater than the controller’s setpoint.
When the sensed temperature increases to the
controller’s setpoint, the A25’s switch will open.
Manual reset is required to reclose the electrical
circuit. The A25 may be used as a high limit control in
the supply air duct (or plenum) where a lockout type
control is desired or required by local code.
Figure 1: The A25 Series Warm Air Control
with Manual Reset
Features and Benefits
Trip-free Reset Lever Does not allow the reset switch to hold the contacts in a closed (on)
position
Pilot Duty Electrical Rating for
up to 600 Volts Maximum
Allows direct control of high voltage motor starters
 Enclosed Switch Protects switch contacts from dust
 Rod and Tube Sensing
Element

Provides maximum response and allows for a high maximum
sensing element temperature
 Adjustable Duct
Mounting Flange

Controls the depth of sensor insertion into the airstream;
compensates for insulation depth
 Wide Temperature Range Allows the A25 to be used with many applications

Johnson Controls A25 Series Specifications

General

Brand	Johnson Controls
Model	A25 Series
Category	Controller
Language	English

Summary

Features and Benefits

Trip-free Reset Lever

Prevents the reset switch from holding contacts in a closed (on) position.

Pilot Duty Electrical Rating

Allows direct control of high voltage motor starters.

Enclosed Switch

Protects switch contacts from dust.

Rod and Tube Sensing Element

Provides maximum response and allows for a high sensing element temperature.

Adjustable Duct Mounting Flange

Controls sensor insertion depth for insulation compensation.

Wide Temperature Range

Allows the A25 to be used with many applications.

Application Overview

Installation

Installation Procedure

Step-by-step guide for mounting the A25 unit in a duct or plenum.

Wiring

Models A25 CN and A25 CP SPDT Wiring

Details wiring for Single Pole Double Throw models, including color coding.

Models A25 AN and A25 AP SPST Wiring

Details wiring for Single Pole Single Throw models and their operation.

Checkout Procedure

Return Air Applications Checkout

Procedures to verify proper operation in return air systems.

Supply Air Applications Checkout

Procedures to verify proper operation in supply air systems.

Operation

Models A25 AN and A25 CN Operation

Explains setpoint adjustment and test/reset procedures for these models.

Models A25 AP and A25 CP Operation

Setpoint Adjustment and Test Procedure

Details how to adjust setpoint and test operation for A25AP/A25CP models.

Dimensions

Repairs and Replacement

Ordering Information

Lists product codes and descriptions for A25 series controls.

Troubleshooting

Troubleshooting Chart

Provides common symptoms, problems, and solutions for the A25 unit.

Notes

Specifications