OEM Carrier Transformer 75VA 208/240/480V to 24VAC for Model PH4GNAA30000AA

This OEM Carrier transformer (part #HT01BD242) is the factory-specified control-circuit transformer for the Carrier PH4GNAA30000AA packaged heat pump/RTU. The transformer steps down high-voltage line power — 208V, 240V, or 480V primary — to the 24VAC secondary signal that energizes your thermostat, contactor coils, gas valve, and control board. When this part fails, nothing in the system responds: the thermostat goes dark, the unit won't call for heating or cooling, and you may measure 0VAC on the 24V circuit. This is the first component to check after a blown control fuse.

• Specs: 75VA power rating | Input: 208/240/480V primary | Output: 24VAC secondary | 50/60 Hz | Foot-mount configuration | OEM part #HT01BD242
• OEM vs Generic: OEM transformers are wound to exact factory VA tolerances — critical for protecting downstream boards and contactors. An undersized or off-tolerance aftermarket unit can over-heat and damage control components far more expensive than the transformer itself.
• Install difficulty: 2/5 — Shut off all power at the disconnect and verify zero voltage with a multimeter before touching any wiring. Label all low-voltage leads before removal. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade terminals. Always test 24VAC output before buttoning up the cabinet.
• Warranty: 1-year OEM factory warranty. In-stock units ship same business day from our warehouse.

Compatibility: Directly replaces the factory transformer in the Carrier PH4GNAA30000AA packaged unit. This part is also used across multiple Carrier, Bryant, Payne, and ICP/Heil/Tempstar platforms that share the same 75VA, multi-tap primary specification — always verify your unit's data plate voltage and VA requirement before ordering. Have a fitment question? Our HVAC parts specialists confirm compatibility before you buy.