Best Johnson Controls in 2026

Single-stage controls

Single-pole

Double-throw

Electronic Single Stage Temperature Control, 120/240 VAC, UL TYPE 1, IP20, SPDT, with 12 amp power c

Featuresa lockable front-panel touchpad for setup and adjustment, and a Liquid Crystal Display (LCD)

Replaces the popular A419 Johnson Control model with upgraded technology.

Wide temperature ranges available

Constant differential throughout the entire range

Compact enclosure

Easy-to-read, bright, adjustable backlit LCD screen displays the temperature

Basic and advanced programming menus allow you to easily set up your control application on the LCD using a simple three-button touchpad interface

Adjustable On and Off temperature set points enable easy to set up cooling or heating

Air connections two (supply and output)

Dials range 55 to 85°f

Sensitivity adjustable from 0.75 to 4.0 psig/°f (9 to 50 kpa/°c)

Type 3R (NEMA) or Type 4 (NEMA) enclosure allows use in indoor or outdoor applications

Viton diaphragms allow use in fluid lines carrying chlorinated water, treated water, or other nonhazardous fluids

low-flow operation on low-flow models actuates switch with less than 1.0 GPM (3.8 L/min) flow for water applications or 9.0 GPM (34.1 L/min) flow for steam applications

Rugged, dependable design

Quality construction provide lasting performance

Superior control technology

All-steel case and cover built to provide long lasting, rugged protection for internal components

Sight-set calibrated pressure adjustment displays a visible pressure scale, fully adjustable through the range without removing the cover (on NEMA 1 enclosure models)

MICRO-SET differential option allows for precise control on low pressure applications

Dual function — monitors current and motor start and stop

100% solid-state output — has no moving parts to fail

Polarity insensitive output — provides easier wiring

Item Package Dimensions:5.1 cm L X5.1 cm W X8.9 cm H

Item Package Weight:0.045 Kilograms

Country Of Origin: United States

Horizontal

White Color

Plastic

Horizontal

Beige Color

Plastic

Brand: Johnson Controls

Product number: A421ABJ-02C

Electronic single stage temperature control, 120

Package Dimensions: 10.5 L x 2.5 H x 3 W (inches)

Package Weight : 1 pounds

Country of Origin : Mexico

Wide temperature ranges available

Constant differential throughout the entire range

Single-pole, single-throw (SPST) or single-pole, double-throw (SPDT) snap-acting switches

Wide temperature range

NEMA 1 enclosure

Use for return air or space temperature sensing

Clear Plastic Guards Have Tumbler-Type Key Locks

Grd10A-608 And -609 Include A Mounting Ring For Mounting To A Wall Or Flat Surface

Plastic baseplate and plastic mounting ring available

All-steel case and cover provides long lasting, rugged protection for internal components

Sight-set calibrated pressure adjustment displays a visible pressure scale, fully adjustable through the range without removing the cover (on NEMA 1 enclosure models)

Manual reset lockout option provides trip-free lockout that cannot be overridden or reset until pressure returns to specified level

Dual function — monitors current and motor start and stop

100% solid-state output — has no moving parts to fail

Polarity insensitive output — provides easier wiring

Attractive beige colored, high-impact plastic enclosure (T26 Series)

Close differential without the need for anticipators

Bi-metal thermometer supplied as standard except where indicated

Small size allows mounting in small enclosure

Solid-state switching contains no moving parts to fail

Low 0.5 ampere activation allows monitoring of most small equipment circuit loads

Clamped/split core design - reduces installation time and associated costs

Slide switch, selectable amperage ranges - provides a wide array of amperage ranges to match the application

Multiple outputs: 4 to 20 mA, 0 to 5 VDC, or 0 to 10 VDC - provide the appropriate output for the specific application

Clamped/split core design - reduces installation time and associated costs

Slide switch, selectable amperage ranges - provides a wide array of amperage ranges to match the application

Multiple outputs: 4 to 20 mA, 0 to 5 VDC, or 0 to 10 VDC - provide the appropriate output for the specific application

Air connections two (supply and output)

Dials range 55 to 85°f

Sensitivity adjustable from 0.75 to 4.0 psig/°f (9 to 50 kpa/°c)

Selectable input types allows use with 0 to 5 VDC (radiometric), 0 to 10 VDC, or 4 to 20 mA input signals from transducers, sensors, and controllers

High input signal selection of two similar inputs (230 or 460 volt models only) provides fan speed control of dual circuit condensing units, based on the highest pressure circuit

Compact design provides for easy and flexible installation

Beige Color

Plastic

with Faceplates

Available in direct acting (dir) and reverse acting (rev) models

Direct acting available in vertical or horizontal T-4506-203

Reverse acting available in horizontal T-4506-203

Available in Direct Acting (DIR) and Reverse Acting (REV) models

Includes Fahrenheit dial

Available in vertical or horizontal model

Rugged, dependable design

Quality construction provide lasting performance

Superior control technology

Plastic