Packard PF42420 Transformer

The Packard PF42420 transformer is a versatile, foot-mounted Class II control transformer engineered for high-demand HVACR applications. As a multi-tap HVAC 24V step-down transformer, it supports primary input voltages of 120V, 208V, and 240V, providing a consistent 24V secondary output rated at 20VA. This unit is designed to replace common field components like the Jard 2031F, UEI UET114, Supco SXT114, and Honeywell AT120A1004. Its foot mount configuration and 18-inch wire lead connections allow for rapid installation in tight control cabinets, making it an essential service truck stock item for residential and light commercial furnace, air handler, and boiler repairs.

Built for the rigors of professional use, this 20VA transformer is rated for over 60,000 hours of continuous operation under standard load conditions. The Class 2 rating ensures the device meets strict safety standards for limiting energy output, effectively protecting sensitive thermostats and solid-state control boards from overcurrent. When installing, technicians should utilize the color-coded primary leads—typically White (Common), Black (120V), Red (208V), and Orange (240V)—to match the local line voltage, ensuring the secondary 24V output remains stable for relays and contactors.

Key Benefits

• Universal Voltage Compatibility: Supports 120/208/240 primary VAC, reducing the number of individual parts needed in inventory.
• High-Durability Design: Engineered for 60,000+ hours of continuous service life to minimize callbacks.
• Broad Cross-Reference: Directly replaces popular 20VA models from Jard, Mars, Honeywell, and Supco.
• Secure Foot Mounting: Features a standard 2-foot base for stable attachment to the equipment chassis or blower housing.
• Pre-Stripped Wire Leads: Simplifies terminal connections in the field, saving time during emergency service calls.

Common Questions

What happens if I use a 20VA transformer on a system requiring 40VA?
Using a lower VA rating than required will cause the transformer to overheat and eventually burn out. Always verify the total volt-ampere demand of the control circuit components (thermostat, contactors, and boards) before installation.

Can this transformer be used in damp environments?
While designed for HVACR equipment interiors, it should be protected from direct water contact and excessive moisture, which can compromise the windings and lead insulation.

How do I identify the correct primary tap for a 208V commercial system?
Refer to the wiring diagram on the unit; typically, you will connect the white (common) and red (208V) leads. Any unused primary leads must be capped with wire nuts to prevent short circuits.

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.