OEM Carrier 40VA Control Circuit Transformer for Model C48A202052

This OEM replacement transformer (part number HT01BD236) is the factory-specified control circuit transformer for the Carrier C48A202052 packaged unit. The transformer steps down line voltage from 120V to the 24V signal required by the thermostat, control board, contactor coil, and all low-voltage control components. When this transformer fails, the entire control circuit goes dead — the thermostat becomes unresponsive, the system won't call for heating or cooling, and no status LEDs illuminate on the control board. It is often the first component to inspect when a unit powers on but does nothing.

• Specs: Primary voltage: 120V | Secondary voltage: 24V | VA rating: 40VA | OEM part number: HT01BD236 | Factory-matched windings and thermal overload protection
• OEM vs Generic: This OEM unit is wound to Carrier's exact VA and impedance specifications, ensuring proper coil voltage delivery under full load. Generic transformers rated at 40VA often fall short under simultaneous contactor and board demand, causing nuisance lockouts and premature failure.
• Install difficulty: 2/5 — Disconnect power at the disconnect box and verify zero voltage with a multimeter before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or quick-connect terminals. Label all wiring before disconnecting. Secondary circuit wiring is straightforward; primary wiring must remain properly strain-relieved.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed specifically for the Carrier C48A202052 packaged unit. Verify your unit's data plate shows 120V primary control circuit voltage before ordering. If your existing transformer shows signs of overheating, also inspect the secondary circuit for shorts before installing the new unit. Questions about fitment? Our HVAC parts specialists confirm compatibility before you order.