OEM Carrier Control Circuit Transformer 40VA for Model C4850C50AY05161

This OEM replacement transformer (part number HT01BD236) is the factory-specified step-down transformer for the Carrier C4850C50AY05161 packaged unit. The transformer converts 120V line voltage down to 24V to power the entire low-voltage control circuit — including the thermostat, contactor coil, gas valve, and control board. When the transformer fails, the result is total control circuit shutdown: the thermostat goes blank, the system won't respond to any call for heating or cooling, and no components can energize. A failed transformer is often mistaken for a bad control board, making correct diagnosis critical before replacing more expensive parts.

• Specs: 40VA rating | 120V primary / 24V secondary | Class 2 transformer | OEM part number HT01BD236 | Factory-matched output for Carrier low-voltage control circuits
• OEM vs Generic: This OEM unit is wound to exact Carrier factory specifications, ensuring stable 24V output under full control circuit load. Off-brand transformers frequently deliver inconsistent voltage, causing nuisance lockouts, erratic thermostat behavior, and premature contactor coil failure.
• Install difficulty: 2/5 — Disconnect power at the breaker before starting. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (verify 0V before touching wiring). Label or photograph all low-voltage wire connections prior to removal. Secure all wire nuts after reinstallation and confirm 24V output before closing the panel.
• Warranty: 1-year OEM factory warranty. Orders placed before 3 PM ship the same business day from our stocked warehouse.

Compatibility: Designed for the Carrier C4850C50AY05161 packaged unit. Always verify the transformer's VA rating and primary/secondary voltage on your unit's wiring diagram or data plate before ordering to ensure a correct fit. Have your model and serial number ready — our technical team is available to confirm fitment before you buy.