Install Instructions

ManualsBrandsJohnson Controls ManualsA421 Series Temperature ControlsSingle Stage Digital Temperature Control (120/240VAC SPDT)

A421 Series Standard Electronic Temperature Controls Installation Instructions

Refer to the QuickLIT website for the most up-to-date version of this document.

Applications

The A421 Series Electronic Temperature Controls are

single-stage, electronic temperature controls with a

single-pole, double-throw (SPDT) output relay.

A421 controls feature a backlit LCD with adjustable

brightness and three-button touchpad interface that

can be set up to restrict user adjustments. An LED

indicates the output relay's On/Off status.

A421 controls have simple On and Off temperature

settings for heating or cooling, an adjustable anti-short

cycle delay, temperature setback, and sensor offset

capability. The temperature control range is

-40to212°F or -40to100°C.

The A421 controls are available either in Type1

(NEMA), IP20 (CE), high-impact plastic enclosures

suitable for surface or DIN rail mounting (Figure 1)

or in Type 4X (NEMA), IP66 (CE) watertight, corrosion

resistant surface mount enclosures (Figure 2).

Dimensions

IMPORTANT: Use this A421 Series Electronic

Temperature Control only as an operating control.

Where failure or malfunction of the A421 control could

lead to personal injury or property damage to the

controlled equipment or other property, additional

precautions must be designed into the control

system. Incorporate and maintain other devices, such

as supervisory or alarm systems or safety or limit

controls, intended to warn of or protect against failure

or malfunction of the A421 control.

IMPORTANT: Utiliser ce A421 Series Electronic

Temperature Control uniquement en tant que

dispositif de régulation. Lorsqu'une défaillance ou un

dysfonctionnement du A421 control risque de

provoquer des blessures ou d'endommager

l'équipement contrôlé ou un autre équipement, la

conception du système de contrôle doit intégrer des

dispositifs de protection supplémentaires. Veiller

dans ce cas à intégrer de façon permanente

d'autres dispositifs, tels que des systèmes de

supervision ou d'alarme, ou des dispositifs de

sécurité ou de limitation, ayant une fonction

d'avertissement ou de protection en cas de

défaillance ou de dysfonctionnement du

A421 control.

Figure 1: A421 Control with Type 1 (NEMA),

IP20 Enclosure Dimensions, in. (mm)

Figure 2: A421 Control with Type 4X (NEMA),

IP66 Enclosure Dimensions, in. (mm)

A421 Series Standard Electronic Temperature

Controls

Installation Instructions

A421ABC-x, A421AEC-x,

A421GBF-x, A421GEF-x

Part No. 24-7664-3019, Rev. D

Issued March 2016

Summary of content (17 pages)

PAGE 1
A421 Series Standard Electronic Temperature Controls Installation Instructions Part No. 24-7664-3019, Rev. D Issued March 2016 A421ABC-x, A421AEC-x, A421GBF-x, A421GEF-x Refer to the QuickLIT website for the most up-to-date version of this document. Applications Dimensions IMPORTANT: Use this A421 Series Electronic Temperature Control only as an operating control.
PAGE 2
Parts Included Mounting Each A421 Control includes a Johnson Controls/ PENN® A99 Series temperature sensor. See A99 Series Temperature Sensors, Wiring, and Technical Specifications for more information about A99 sensors. Observe the following guidelines when locating and mounting an A421 control: • Ensure that the mounting surface can support the control, DIN rail, mounting hardware, and any (user-supplied) panel or enclosure. • Mount the control in a vertical, upright orientation wherever possible.
PAGE 3
Wiring 3. Position the control mounting slots over the screw heads, and then carefully tighten the mounting screws to secure the control to the surface. ! 4. When mounting the control on an uneven surface, use shims to mount the control evenly on the surface. Additional Guidelines for Mounting Type 4X/IP66 Controls The Type 4X models may be mounted to flat vertical surfaces using the four holes at the enclosure corners.
PAGE 4
Table 1: Maximum Recommended Sensor Cable Lengths and Wire Sizes IMPORTANT: When connecting an A99 sensor with a shielded cable to an A421 Control, connect the cable shield drain lead to the COM (common) terminal on the sensor and binary input terminal block (TB3). Do not connect the shield at any other point along the cable, and isolate and insulate the shield along the entire length of the sensor cable.
PAGE 5
Figure 4: Wiring the A421 Series Controls Using the Same Power Source to Power the Control Operation and Power the Controlled Equipment Table 2: A421 Control Wiring Terminals and Wire Size Information (Part 1 of 2) Terminal Block Label Description, Function, and Requirements Recommended Wire Sizes TB1 24 VAC Models LN Low-Voltage 24 VAC Control Power (Common): Connect the 24 VAC supply power to operate the control. 28 AWG to 12 AWG 0.08 mm2 to 4.
PAGE 6
Table 2: A421 Control Wiring Terminals and Wire Size Information (Part 2 of 2) Terminal Block Label Description, Function, and Requirements Recommended Wire Sizes TB3 BIN Detects a switch closure between the BIN and COM terminals and enables the selected temperature setback (tSb) value. COM Connects low-voltage common from the sensor and binary input. 22 AWG (0.34 mm2) stranded, shielded cable recommended SEN Connects low-voltage input signal wire from control sensors.
PAGE 7
Anti-Short Cycle Delay (ASd): Select the minimum time that the output relay remains off (de-energized) before the next on-cycle can start. The ASd interval overrides any load demand (On) and does not allow the output relay to go on until the selected ASd interval has elapsed. See Figure 6. Three-Button Touchpad The touchpad has three buttons for setup and adjustment of the A421 control (Figure 5). See Menu Navigation Guidelines on page 9 for more information on using the three-button touchpad.
PAGE 8
• Temperature Units (Un): Select the desired temperature scale for your application. Select either the Fahrenheit (°F) or Celsius (°C) temperature scale. Note: After changing the temperature units value (Un), confirm that the temperature values for the other parameter codes are still correct for your application. Note: The control displays only the original On and OFF values in both the normal and setback modes.
PAGE 9
A421 Control Parameter Setup Menus The A421 temperature controls provide a Basic and an Advanced setup menu that allow you to scroll through the parameter setup codes, view and edit parameter values, and set up your control for your application requirement. The control also has a Restricted (adjustment) menu. See Restricting User Adjustment for more information. Note: The A421 control retains a copy of the saved parameter values in memory.
PAGE 10
Viewing and Changing Values in the Advanced Menu To exit the Basic menu and go directly into the Advanced menu, simultaneously press  and , and hold them for 5 seconds.
PAGE 11
• The control band (differential) is defined by the On and OFF values, and the control band between On and OFF remains fixed (not adjustable). • Only the OFF value can be adjusted, the control band remains fixed, and the On value automatically shifts equal to the OFF value adjustment. • The OFF value can only be adjusted to values that maintain the entire control band within the restricted temperature adjustment range defined by HtS and LtS. See Figure 9.
PAGE 12
5. Press  and  simultaneously to return to the Main screen. Troubleshooting Fault Codes A421 Series controls display fault codes on the LCD as described in Table 5. Figure 11: Adjusting Temperature in the Restricted Menu Table 5: Fault Codes Defined Fault Code Definition System Status Solution SF flashing alternately with OP Open temperature sensor or sensor wiring Output functions according to the selected sensor failure mode (SF) See Troubleshooting Procedure. Cycle power to reset the control.
PAGE 13
f. g. If the sensor’s measured resistance value is substantially different from the expected value for that temperature, check the sensor wiring. If sensor wiring is correct, replace the sensor. Press MENU until On appears. Press MENU again to display the On value. g. Press  or  to change the On temperature above and below the sensor temperature until the relay energizes and de-energizes.
PAGE 14
Table 6: A421 Series Standard Electronic Temperature Controls Selection Chart (Part 2 of 2) Product Type Description A421AEC-02C Line-Voltage Type 4X Electronic Temperature Control: Type 4X (NEMA), IP66 watertight enclosure for surface-mount applications. Rated for 120/240 VAC. Includes an A99BB-200C temperature sensor with 6.6 ft (2.0 m) cable. A421GBF-02C Low-Voltage Type 1 Electronic Temperature Control: Type 1 (NEMA), IP20 standard enclosure for DIN rail and surface-mount applications.
PAGE 15
Table 8: Accessories (Part 2 of 2) PLT344-1R Two End Clamps for DIN rail sections A99-CLP-1 Surface Mounting Clip for A99B and A99C Series Temperature Sensors SHL10-603R Sun Shield for A99B and A99C Series Temperature Sensors BOX10A-603R PVC Enclosure for A99B and A99C Series Temperature Sensors WEL11A-601R Copper and brass immersion well for applying sensor in fluid applications TE-6300W-102 Stainless steel immersion well for applying A99 sensors in fluid applications.
PAGE 16
Table 11: UL Conformity Declaration Information (Part 2 of 2) External Pollution Situation All Models: A421 [ ] B: Pollution Degree 3 All Models: A421 [ ] E: Pollution Degree 4 Internal Pollution Situation Pollution Degree 2 Heat and Fire Resistance Category D Rated Impulse Voltage 4000 V Ball Pressure Temperature 128 C Cover Screw Torque Requirements Instruction All Models: A421 [ ] E: To Maintain Type 4X / IP66 Rating, Tighten Enclosure Screws to: 10 - 12 in·lb Table 12: A99B Series Positive T
PAGE 17
European Single Point of Contact: NA/SA Single Point of Contact: APAC Single Point of Contact: JOHNSON CONTROLS WESTENDHOF 3 45143 ESSEN GERMANY JOHNSON CONTROLS 507 E MICHIGAN ST MILWAUKEE WI 53202 USA JOHNSON CONTROLS C/O CONTROLS PRODUCT MANAGEMENT NO. 22 BLOCK D NEW DISTRICT WUXI JIANGSU PROVINCE 214142 CHINA Building Efficiency 507 E. Michigan Street, Milwaukee, WI 53202 Johnson Controls® and PENN® are registered trademarks of Johnson Controls, Inc.