Multi Mount 120V (Primary) 24V (Secondary) 40VA Transformer

The Packard PM12440 is a Class 2 transformer that converts standard 120V primary power to 24V secondary output with a 40VA rating. This multi-mount unit is built to replace equal or lower VA rated transformers across a wide range of HVAC systems, providing the reliable 24-volt control power needed for thermostats, zone controls, and heating equipment. With its included 4-1/4" x 4-1/4" mounting plate and 1/2" conduit hub for electrical knockout mounting, this transformer adapts to virtually any installation scenario. It ships with wire lead connections ready for direct integration into existing control circuits.

• Multi-Mount Design: Includes a 4-1/4" x 4-1/4" mounting plate and 1/2" conduit hub for electrical knockout mounting, giving you installation flexibility whether you're working with a furnace cabinet, junction box, or wall-mounted panel. This versatility means one transformer can handle multiple job site scenarios without requiring separate inventory.

• 120V Primary to 24V Secondary: Steps down standard line voltage to the 24-volt control voltage used by most residential and light commercial HVAC controls. This precise conversion ensures compatible, stable power for thermostats and zone control boards.

• 40VA Power Rating: Delivers 40 volt-amperes of power capacity, sufficient for typical single-zone thermostat and control circuits. This rating supports the power draw of digital thermostats, relays, and zone dampers without overloading.

• Class 2 Transformer Classification: Meets Class 2 electrical safety standards, limiting output current and power to levels that reduce fire and shock hazards. This classification simplifies installation by allowing the use of thermostat wire without conduit in many jurisdictions.

• Wire Lead Connection: Features direct wire leads on both primary and secondary sides for straightforward field wiring. You can splice, terminate to screw terminals, or connect directly to existing control wiring without adapters.

• Broad OEM Compatibility: Packard PM12440 directly replaces models from Lennox (13N4801), Jard (4011M), Mars (50213, 50302), Robertshaw (620-403), White-Rodgers (90-4011M, 90T40M1), Honeywell (AT140A1000, AT140C1022, AT72D1683), Global (GT4011M), Supco (SXT112), Interstate Electric (T100E), Armstrong (TPF124-40), and Trane (TRR1004). This cross-reference capability lets you consolidate stock and reduce callbacks when the original part number is unavailable.

This transformer is designed to replace any transformer with an equal or lower VA rating across residential and light commercial HVAC systems. It works with standard 120V AC line voltage on the primary side and outputs 24V AC on the secondary side for control circuits. The multi-mount configuration adapts to plate mounting, conduit knockout mounting, or direct fastening, fitting applications from furnaces and boilers to zone control panels and air handlers. The Class 2 rating makes it compatible with low-voltage thermostat wiring installations.

Mount the transformer using the included 4-1/4" x 4-1/4" mounting plate on any suitable surface, or install directly through a 1/2" electrical knockout using the integrated conduit hub. Connect 120V line voltage to the primary leads and run 24V control wiring from the secondary leads to your thermostat or control board. The wire lead design allows for splicing or terminal connections depending on your specific panel configuration. No ongoing maintenance is required beyond standard electrical system inspections.

A: VA stands for volt-amperes, the measure of apparent power the transformer can deliver. A 40VA rating means this transformer can supply up to 40 volt-amperes of power to the 24-volt control circuit, which is sufficient for most single-zone residential thermostat and relay applications. This capacity handles the draw of digital thermostats, zone dampers, and typical HVAC control boards without overloading.

A: Yes, the Packard PM12440 directly replaces the Honeywell AT140A1000. It also replaces Honeywell AT140C1022 and AT72D1683, along with models from Lennox, Mars, White-Rodgers, Robertshaw, and other manufacturers listed in the cross-reference. Packard transformers replace any model with an equal or lower VA rating, so the 40VA PM12440 fits wherever a 40VA or smaller transformer was originally installed.