OEM Carrier Transformer 40VA 120V/24V for Model C50A503061

This OEM replacement transformer (part number HT01BD236) is the factory-specified control circuit transformer for the Carrier C50A503061 commercial packaged unit. The transformer steps down line voltage from 120V to the 24V AC signal that powers your thermostat, control board, and all low-voltage switching circuits. When this component fails, the entire control circuit goes dark — your thermostat will be completely unresponsive, relays won't energize, and the system will not heat or cool regardless of thermostat commands.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | Factory-matched impedance and thermal protection | Fits Carrier OEM mounting footprint
• OEM vs Generic: The OEM HT01BD236 transformer is wound to exact VA and voltage specifications Carrier engineers designed for this unit. Undersized or off-tolerance generic transformers can overheat, trip the internal fuse, or cause erratic low-voltage behavior that mimics control board failure — leading to costly misdiagnosis.
• Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: multimeter, flathead and Phillips screwdrivers, wire stripper, needle-nose pliers. Always verify 24V output at secondary terminals after installation before restoring control wiring.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier C50A503061 commercial rooftop/packaged unit. Confirm your existing transformer's VA rating and primary voltage on the unit data plate or wiring schematic before ordering. If your thermostat display is blank and your control board shows no activity, test transformer secondary output first — this is the most common and most overlooked fix. Questions about fitment? Our HVAC parts specialists verify compatibility before you order.