CaptiveAire A25AN User Manual

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.

FANs 125, 121

Product/Technical Bulletin A25

Issue Date 0796

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

❑

Enclosed Switch Protects switch contacts from dust

❑

Rod and Tube Sensing Element

❑

Adjustable Duct Mounting Flange

❑

Wide Temperature Range Allows the A25 to be used with many applications

Allows direct control of high voltage motor starters

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

Controls the depth of sensor insertion into the airstream; compensates for insulation depth

Part 24-7664-656, Rev.— Code No. LIT-125118

pplication Overview

A typical application for the A25 Series Warm Air Control with Manual Reset is to stop the operation of air conditioning or ventilating fans upon a temperature rise. Models A25AP and A25CP are Factory Mutual approved for use as fire protection devices.

3. Using the flange as a template on the duct, mark the location for two 1/2 in. (13 mm) No. 10 sheet metal screws.

4. Punch (or drill) both sheet metal screw holes in the duct at the marked locations.

5. Secure the flange to the duct with two 1/2 in. (13 mm) No. 10 sheet metal screws provided.

nstallation

1. Select a mounting location for the A25 in the duct (or plenum). The location must allow the sensing element to sense the average temperature in the duct.

2. Drill (or cut) a 1-3/8 in. hole in the duct at the selected mounting location (refer to Figure 2).

6. Insert the sensing element and sleeve through the flange installed in Step 5 (and into the duct).

7. Secure the A25 to the flange by screwing the set screw firmly against the sleeve. Do not overtorque the set screw.

Note: Insert the sensing element as far as possible

into the air stream without allowing it to contact any object inside the duct. Provide at least 5-3/4 in. (14 cm) clearance between the sensor and any other objects inside the duct.

Figure 2: Installing the A25

2 A25 Series Warm Air Control with Manual Reset Product/Technical Bulletin

iring

WARNING: Shock hazard. To avoid

electrical shock or damage to equipment, disconnect all power before making wiring connections.

If available, follow the instructions for the unit onto which the A25 will be installed. Make all wiring connections only with copper conductors and in accordance with the National Electrical Code and local regulations. Refer to the label inside the A25’s cover for the maximum electrical rating.

Models A25CN and A25CP SPDT (Single Pole Double Throw) Units

The wiring terminals on the SPDT (Single Pole Double Throw) models are color coded:

●

Red is common.

●

The red to yellow circuit closes on temperature increase.

Figure 3: Terminal Identification for

A25CN and A25CP SPDT Models

Figure 4: Typical Wiring Diagram of

A25CN and A25CP SPDT Models

●

The red to blue circuit opens on temperature increase.

Refer to Figures 3 and 4 for terminal identification and typical wiring connections.

When the reset lever is pressed during normal operation, the trip free contacts are activated, the red to blue contact opens and the auxiliary red to yellow contact closes. At this point, the auxiliary system will activate.

Models A25AN and A25AP SPST (Single Pole Single Throw) Units

When the temperature increases to above the setpoint, the circuit opens. When the reset lever is pressed after the sensed temperature decreases to approximately 20F° (11C°) below the setpoint, the circuit closes.

Refer to Figures 5 and 6 for terminal identification and typical wiring connections.

IMPORTANT: Only use the terminal screws

furnished with the A25 (8-32 x 1/4 in. binder head). Use of other screws will void warranty, may damage switch terminals, and result in improper connections.

Figure 5: Terminal Identification for

A25AN and A25AP SPST Models

Figure 6: Typical Wiring Diagram for

A25AN and A25AP SPST Models

A25 Series Warm Air Control with Manual Reset Product/Technical Bulletin 3

heckout Procedure

peration

After installing the A25, perform the following procedures. Observe at least three complete operating cycles to verify that all components are functioning properly. If the unit fails to checkout, refer to the troubleshooting chart (Table 2). Do not attempt to make adjustments.

Return Air Applications

1. After completing the installation and wiring procedures, turn on the power to the circuit.

2. Turn the setpoint knob counterclockwise until the A25 shuts down the system.

The A25 should lockout and the alarm or signal (if applicable) should activate.

Note: The setpoint at shutdown should equal the

approximate duct air temperature.

3. Turn the setpoint knob clockwise to the desired setpoint.

Nothing should happen.

4. Press the reset lever.

The system should restart and the alarm or signal (if applicable) should shut off.

Models A25AN and A25CN

Setpoint Adjustment: Adjust the A25 setpoint by

rotating the setpoint knob (Figure 7). The setpoint is displayed in the setpoint window.

Test Procedure:

To test (trip) the A25: Raise the temperature

at the sensor above the setpoint or lower the setpoint below the ambient temperature.

control should lockout (trip).

To reset after test: Lower the temperature at the sensor to 20F° (11C°) below the setpoint or raise the setpoint to 20F° (11C°) above the ambient temperature. Press the reset lever. The A25 should reset (closing the circuit).

Reset Procedure: Verify that the temperature has dropped to 20F° (11C°) below setpoint. Press the reset lever to reset the A25 (closing the circuit).

The

Supply Air Applications

1. After completing the installation and wiring procedures, turn on the power to the circuit.

2. Raise the supply air temperature to the setpoint temperature.

Note: The supply air temperature can be raised

by simulating a fan failure or restricting the return air flow.

3. When the system shuts down, determine the temperature at the A25 sensing element.

The temperature reading should closely approximate the A25’s setpoint at which the system is shut down and (if applicable) the alarm or signal is activated.

4. Return the system to normal operation by re-establishing air flow or by restarting the fan.

5. Press the reset lever.

The system should restart and the alarm or signal (if applicable) should shut off.

Figure 7: Models A25AN and A25CN

4 A25 Series Warm Air Control with Manual Reset Product/Technical Bulletin

Models A25AP and A25CP

Setpoint Adjustment: Loosen the cover screw

(Figure 8) and remove the cover. Adjust the setpoint by rotating the adjusting screw. When adjusted, re-install the cover. Tighten cover screw.

Test Procedure:

To test (trip) the A25: Raise the temperature

at the sensor above the setpoint or lower the setpoint below the ambient temperature.

control should lockout (trip).

Reset Procedure: Verify that the temperature has dropped 20F° (11C°) below setpoint. Press the reset lever to reset the A25 (closing the circuit).

imensions

The

Figure 8: Models A25AP and A25CP

Figure 9: A25 Dimensions, in./mm

A25 Series Warm Air Control with Manual Reset Product/Technical Bulletin 5

epairs and Replacement

Do not make field repairs. For a replacement control, contact your nearest Johnson Controls representative.

Table 1: Ordering Information

Item Product Code

Number

A25 Series Warm Air Control with Manual Reset

roubleshooting

A25AN-1 A25AP-1

A25CN-1 A25CP-1

Table 2: Troubleshooting Chart

Symptom Problem Solution

The A25 is not sensing properly.

The system does not operate.

A25 does not lockout upon a temperature rise beyond the setpoint.

The A25 does not sense the correct air temperature.

A25 will not reset.

Product

Description

SPST, opens on temperature rise, setpoint knob adjustment. SPST, opens on temperature rise, concealed screwdriver adjustment,

Factory Mutual approved. SPDT, setpoint knob adjustment. SPDT, concealed screwdriver adjustment, Factory Mutual approved.

The sensing element may not be extended into the airstream or the sensing element is contacting an object inside of the duct (or plenum).

Incorrect switch connections or improper wiring.

Damaged sensor. The A25 is tripped. The A25 is defective. Replace the A25.

The A25 is defective. Replace the A25.

The temperature in the duct (or plenum) is not 20F° (11C°) below the setpoint.

Insert the sensing element as far as possible into the airstream without allowing it to contact any object inside the duct (or plenum).

Ensure that the wiring connections follow the wiring diagrams in the

Check connections. Replace the A25. Reset the A25.

Check system for overheating or fire.

Wiring

section.

6 A25 Series Warm Air Control with Manual Reset Product/Technical Bulletin

Notes

A25 Series Warm Air Control with Manual Reset Product/Technical Bulletin 7

pecifications

Product

Range

Electrical Ratings Volts, AC 120 VAC 208 VAC 240 VAC 277 VAC

Ambient Temperature

(Maximum)

Conduit Opening

Switch

Cover Finish

High Limit Dial Stop

Material

Mounting

Reset

Sensing Element

Shipping Weight

Wiring Connections

Agency Listing

* FLA = Full Load Amps; LRA = Locked Rotor Amps. Values are equivalent to a 1 HP motor rating in accordance with UL353.

The performance specifications are nominal and conform to acceptable industry standards. For application at conditions beyond these specifications, consult the local Johnson Controls office. Johnson Controls, Inc. shall not be liable for damages resulting from misapplication or misuse of its products.

A25AN-1 SPST, opens on temperature rise, setpoint knob adjustment. A25AP-1 SPST, opens on temperature rise, concealed screwdriver adjustment,

Factory Mutual approved. A25CN-1 SPDT, setpoint knob adjustment. A25CP-1 SPDT, concealed screwdriver adjustment, Factory Mutual approved. 25 to 215°F (-4 to 102°C)

Motor FLA*

Motor LRA*

Noninductive A

Case 104°F (40°C) Element 300°F (149°C)

7/8 in. (22 mm) diameter hole for 1/2 in. conduit Snap-acting contacts in dust protected enclosure Gray baked enamel 125°F Case 0.063 in. (1.6 mm) galvanized steel

Cover 0.025 in. (0.64 mm) cold rolled steel Flange for flat surface Positive, trip-free reset mechanism (manual reset 2 operation). Control can be reset when

the temperature drops 20F° (11C°) below the dial setting. Bi-metal rod and tube construction Individual pack 1.8 lb. (0.8 kg)

Overpack of 12 units 23 lb. (10.4 kg) Screw-type terminals UL Recognized: File MP640, Guide MBPR

CSA Certified: File LR948, Class 4813 02 Factory Mutual Approved (Models A25AP and A25CP only): Class 3545

16 9.2 8 96 55.2 48 16 16 16 16

Pilot Duty: 125 VA at 24/600 VAC

Controls Group

507 E. Michigan Street P.O. Box 423 Milwaukee, WI 53201 Printed in U.S.A

8 A25 Series Warm Air Control with Manual Reset Product/Technical Bulletin