OEM Carrier 40VA Control Transformer for Model PH3GEAA48000AA

This is the factory-specified OEM replacement control transformer for the Carrier PH3GEAA48000AA packaged HVAC unit. The transformer steps down the 120V line voltage to the 24V signal used by your thermostat, control board, contactor coils, and all low-voltage safety circuits. When the transformer fails, the entire control circuit goes dead — your thermostat goes blank, the system will not respond to any call for heating or cooling, and there is no low-voltage output at any terminal. This is one of the first components to check when a unit shows zero response across the board.

• Specs: Input: 120V AC | Output: 24V AC | VA Rating: 40VA | OEM Part Numbers: HT01BC701 / HT01BD242 | Factory-matched windings and insulation class
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances for the Carrier PH3GEAA48000AA platform. Generic substitutes frequently run under-rated VA, causing thermal overloads and repeat failures — especially in systems with multiple 24V accessories like humidifiers, zone boards, or UV lights.
• Install Difficulty: 2/5 — Always disconnect power at the disconnect box and verify zero voltage before touching any wiring. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Photograph all wire connections before removal. Confirm secondary output voltage with a multimeter after installation before closing the cabinet.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse.

Compatibility: Engineered as a direct OEM replacement for the Carrier PH3GEAA48000AA packaged unit. Cross-references OEM part numbers HT01BC701 and HT01BD242 — both numbers supersede to the same component. Verify your existing transformer's input/output voltage and VA rating on the data plate before ordering to ensure correct fitment. Have a question about compatibility? Our HVAC parts specialists verify fitment before you buy — contact us today and get your unit back online fast.