OEM Carrier 75VA Control Transformer HT01BD242 for Model PH4GNXB42000AA

This is the genuine OEM factory-specified control transformer for the Carrier PH4GNXB42000AA packaged heat pump unit. The transformer steps down the high-voltage primary supply (208/240/480V) to the 24V AC signal required to power the entire low-voltage control circuit — including the thermostat, contactor coil, and control board. When this transformer fails, the result is total system silence: no thermostat response, no fan, no compressor. It is one of the most critical components in the control circuit and is often overlooked during diagnosis.

• Specs: 75VA rating | Primary: 208/240/480V | Secondary: 24VAC | 50/60Hz | Foot-mount configuration | OEM part number HT01BD242
• OEM vs Generic: This is a genuine Carrier OEM transformer wound to exact VA and voltage tolerances. Undersized or off-tolerance aftermarket transformers can overheat, trip thermal cutouts, and damage connected control boards — always match the OEM VA rating precisely.
• Install difficulty: 3/5 — Requires disconnecting 120V–480V primary wiring. Always shut off the disconnect and verify zero voltage with a multimeter before touching any terminals. Tools needed: multimeter, screwdrivers, wire nuts or spade terminals. Label all wires before removal.
• Warranty: 1-year OEM manufacturer warranty. In-stock orders ship same business day from our warehouse.

Compatibility: Designed as the direct factory replacement for Carrier model PH4GNXB42000AA packaged heat pump units. The 75VA rating and multi-tap primary (208/240/480V) make this transformer compatible across a range of Carrier packaged and split systems — always verify your unit's data plate voltage and VA spec before ordering. Have a fitment question? Our HVAC parts specialists verify compatibility before you buy.