Resideo AT140B1206 Transformer

The Resideo AT140B1206 Transformer is a heavy-duty, foot-mounted solution designed for powering 24V control systems in residential and light commercial HVAC applications. Engineered with a 120V primary to 27V secondary winding, this 40VA transformer provides a stable power supply for thermostats, gas valves, and relays. It features integrated plastic end caps for terminal protection and enhanced safety during field installation. As a direct replacement for B1408403, this unit ensures seamless compatibility for contractors servicing older equipment. The Class 2 power supply rating and NEMA type transformer construction make it a reliable choice for HVAC control circuit replacement. Whether you are troubleshooting a failed 24V step-down transformer or performing a system upgrade, this Resideo multi-tap transformer alternative offers the durability required for high-cycle environments. Its compact footprint allows for flexible mounting within air handlers or furnace cabinets, ensuring efficient low voltage transformer wiring without unnecessary footprint constraints.

• High Power Capacity: Rated at 40VA to handle multiple control components simultaneously.
• Circuit Protection: Includes plastic end caps to prevent accidental shorts at connection points.
• Universal Mounting: Foot-mounted design facilitates quick installation in various cabinet configurations.
• Proven Compatibility: Replaces common industry part numbers including B1408403.
• Stable Output: 27V secondary output accounts for voltage drop in complex control loops.

What is the maximum load for this 40VA transformer?
The unit supports a maximum load of 1.6 Amps at 24-27VAC; exceeding this may cause thermal overload or fuse failure in the control circuit.

Can this transformer be used in 208V/240V systems?
No, the AT140B1206 is specifically engineered for 120V primary input. For 208/240V applications, a multi-tap primary model must be utilized.

Does this unit include internal fusing?
This model is impedance protected but does not contain an integrated replaceable fuse; we recommend installing an inline 3-amp fuse on the secondary side to protect the winding.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.