OEM Carrier Control Transformer 40VA 120V/24V for Model C48A403052

This is the OEM factory-specified replacement transformer (part number HT01BD236) for the Carrier C48A403052 packaged unit. The transformer steps down line voltage from 120V to 24V to power the entire low-voltage control circuit — including the thermostat, contactor coil, and control board. When the transformer fails, the result is total control-circuit loss: a blank thermostat, an unresponsive system, and no heating or cooling whatsoever. If you've already confirmed 120V supply is present but your 24V control circuit reads zero, this transformer is the most likely culprit.

• Specs: 40VA rating | Primary: 120V | Secondary: 24V | OEM part number HT01BD236 | Factory-matched output tolerance for stable low-voltage control
• OEM vs Generic: This OEM transformer is wound and rated to Carrier's exact specifications. Generic alternatives often use lower-grade core laminations that overheat under sustained load, causing nuisance tripping or premature failure — especially in packaged units with longer run cycles.
• Install difficulty: 2/5 — Shut off power at the disconnect before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or spade terminals. Label or photograph all low-voltage wiring connections before disconnecting. Verify incoming 120V and outgoing 24V with a meter after installation.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier C48A403052 packaged unit. Always verify your existing transformer's VA rating and primary/secondary voltages against your unit's wiring diagram before ordering. If you have any fitment questions, our HVAC parts specialists can confirm compatibility before you buy — same-day shipping on all stocked OEM parts.