OEM Carrier Control Transformer 75VA 208/240/480V–24V for Model PH4GPAA42000AA

This is the factory OEM replacement transformer (part #HT01BD242) for the Carrier PH4GPAA42000AA packaged heat pump unit. The transformer steps down high-voltage primary power — 208V, 240V, or 480V — to the 24V AC signal that powers your thermostat, contactor coils, and all low-voltage control circuits. When this transformer fails, the result is total loss of control voltage: the thermostat goes blank, the system refuses to respond to calls for heating or cooling, and no components energize. Replacing it is one of the highest-impact single-part repairs you can make.

• Specs: 75VA rating | Primary: 208/240/480V | Secondary: 24VAC | 50/60Hz | Foot-mount configuration | OEM part #HT01BD242
• OEM vs Generic: This is a genuine Carrier factory-authorized part, engineered to exact VA rating and insulation class. Undersized or off-brand transformers can overheat under full control-circuit load, causing intermittent faults and shortened service life.
• Install difficulty: 3/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: multimeter (to verify 0V before touching terminals), flathead and Phillips screwdrivers, needle-nose pliers, wire labels. Always photograph existing wiring connections before disconnecting. Verify primary voltage tap matches your supply voltage.
• Warranty: 1-year OEM manufacturer warranty. In-stock orders ship same business day from our warehouse.

Compatibility: Engineered for the Carrier PH4GPAA42000AA packaged heat pump unit. This transformer is also cross-referenced for use in compatible Carrier, Bryant, Payne, and ICP family equipment sharing the HT01BD242 specification. Confirm your unit's primary supply voltage (208V, 240V, or 480V) matches the appropriate tap before installation. Not sure it fits? Contact our parts team — we verify fitment before you order.