OEM Carrier 40VA Control Transformer for Model C50A305051 — Part# HT01BD236

This is the OEM factory-replacement control transformer for the Carrier C50A305051 commercial packaged unit. The transformer steps down 120V line voltage to the 24V signal required by your thermostat, contactor coil, gas valve, and all other low-voltage control components. When this transformer fails, the entire control circuit loses power — the result is a completely unresponsive system: no thermostat communication, no contactor pull-in, no ignition sequence, and no fan operation. If your system is completely dead despite confirmed line voltage at the unit, a failed transformer is one of the first components to test with a multimeter.

• Specs: 40VA rated | Primary: 120V | Secondary: 24V | OEM Part Number: HT01BD236 | Factory-matched output tolerance for reliable low-voltage control circuit operation
• OEM vs Generic: This OEM transformer is wound and rated to Carrier's exact factory specifications. Generic aftermarket transformers frequently carry undersized VA ratings that cause nuisance trips under full control-circuit load, leading to repeat failures and diagnostic confusion.
• Install Difficulty: 2/5 — Always disconnect power at the disconnect box and verify zero voltage with a multimeter before beginning work. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Label or photograph all wire connections before removal. Secondary wiring typically connects to the R and C terminals of the control board.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse when ordered before cutoff.

Compatibility: Engineered specifically for the Carrier C50A305051 commercial rooftop/packaged unit. Verify primary voltage (120V) and VA rating (40VA) against your unit's wiring diagram and data plate before ordering. Not sure if this is the right part? Our HVAC parts specialists confirm fitment before you buy — reach out before placing your order.