OEM Carrier Control Circuit Transformer HT01BD242 for Model PH4GEAA36000AA

This is the OEM factory-specified step-down transformer for the Carrier PH4GEAA36000AA packaged heat pump unit. The transformer converts 120V line voltage to 24V AC, powering the entire low-voltage control circuit — including the thermostat, contactor coil, and control board. When this transformer fails, nothing in the system responds: the thermostat goes dark, the unit won't call for heating or cooling, and no fault codes appear on the board because there is no control voltage to drive them.

• Specs: Input: 120V AC | Output: 24V AC | 40 VA rating | OEM part number HT01BD242 | Factory-matched windings and thermal protection
• OEM vs Generic: This OEM transformer is wound to exact Carrier factory specifications, including proper VA capacity and insulation class. Generic replacements often underrate VA, causing overheating under full control-circuit load and premature failure.
• Install Difficulty: 2/5 — Disconnect all power before beginning. Tools needed: multimeter (to confirm 0V before touching terminals), flathead and Phillips screwdrivers, wire stripper, needle-nose pliers. Always photograph existing wiring before disconnecting. Verify output voltage after installation before restoring full system power.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed and tested for the Carrier PH4GEAA36000AA packaged heat pump unit. Verify input voltage (120V) and VA rating on your unit's data plate before ordering. If you're unsure of fitment, our HVAC parts specialists confirm compatibility before you buy — reach out before placing your order.