Johnson Controls A421AEC-02C Single Stage Digital Temperature Control with 6 Ft. 7-1/5" Leads (120/240v, SPDT) Temperature Controller
Regular price $167.04The Johnson Controls A421AEC-02C Single Stage Digital Temperature Control with 6 Ft. 7-1/5" Leads (120/240v, SPDT) Temperature Controller is a Johnson Controls temperature controller for HVAC repair and replacement work. Use it when the part number A421AEC-02C and the listed specifications match the equipment being serviced.
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. The A421 Series controls are single stage, electronic temperature controls with a single-pole, double-throw (SPDT) output relay. The controls feature an adjustable backlit LCD for viewing the temperature and status of other functions, and a three-button touchpad for setup and adjustment. An LED indicates the On/Off status of the output relay. The A421 controls are available in low voltage 24 VAC and high voltage 120 or 240…
Key Specs
- Product Type: Temperature Control
- Voltage: 120/240V
- Application: Temperature Control
Replacement Notes
Captured replacement references include A421AEC-2C, A99BB-200C. Confirm supersession details against the manufacturer parts list.
Expert Verdict
Reviewed by the SuperArbor Pro Desk: choose this part when the existing component label and unit documentation match A421AEC-02C and the spec set above. It is best suited for targeted HVAC service repairs where exact fitment matters more than broad universal compatibility.
FAQs
What is the Johnson Controls A421AEC-02C used for?
It is a temperature controller for compatible Johnson Controls HVAC equipment. Match the part number A421AEC-02C and the equipment service literature before ordering or installing.
Which specs should I verify before purchase?
Verify the spec set shown for this part: Product Type: Temperature Control; Voltage: 120/240V; Application: Temperature Control. The replacement should match the existing component and the unit documentation.
Does the electrical rating need to match exactly?
Yes. Confirm voltage rating 120/240V against the failed component label. Do not substitute a different rating unless the equipment manufacturer allows it.
Are replacement or superseded references available?
Captured cross-reference data includes A421AEC-2C, A99BB-200C. Verify any supersession directly against the manufacturer parts list before installation.
Who should install this HVAC component?
A qualified HVAC technician should install and test the temperature controller. Disconnect power first, follow lockout procedures, and confirm safe operation after replacement.
Safety and Installation Notes
Disconnect power before service. HVAC electrical and combustion-related components should be installed and tested by a qualified technician. After installation, confirm wiring, mounting, airflow or fluid routing as applicable, and normal system operation.
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