OEM Carrier Control Transformer 40VA 120V/24V for Model C4850C50AW05151

This OEM replacement transformer (part number HT01BD236) is the factory-specified control circuit transformer for the Carrier C4850C50AW05151 packaged unit. The transformer steps line voltage (120V) down to 24V to power the low-voltage control circuit — including the thermostat, contactor coil, and control board. When this component fails, the entire control circuit goes dead: your thermostat loses power, the unit stops responding to calls for heating or cooling, and no fault codes are generated because the board itself has no power. A failed transformer is often misdiagnosed as a thermostat or control board failure, making correct identification critical before replacing more expensive components.

• Specs: 40VA rating | Primary: 120V | Secondary: 24V | OEM part number HT01BD236 | Factory-matched for Carrier C4850C50AW05151 packaged systems
• OEM vs Generic: This OEM transformer meets Carrier's exact VA rating and insulation class specifications. Undersized or off-brand transformers can overheat under peak control-circuit load, causing nuisance lockouts or premature failure — especially in systems with zone boards or accessories drawing additional 24V current.
• Install difficulty: 2/5 — Disconnect power at the disconnect box and confirm voltage is absent before servicing. Tools needed: flathead and Phillips screwdrivers, multimeter (to confirm primary voltage and verify 24V output after install), wire nuts or spade connectors. Always document existing wiring with photos before disconnecting terminals.
• Warranty: 1-year OEM factory warranty against defects. In-stock and ships same business day from our warehouse.

Compatibility: Engineered and factory-matched for the Carrier C4850C50AW05151 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages against your unit's data plate before ordering. If you're unsure of fit, our HVAC parts specialists confirm compatibility before your order ships — no guesswork required.