OEM Carrier 40VA Control Transformer for Model C4850C50AJ02061

This OEM Carrier transformer (part# HT01BD236) is the factory-specified step-down transformer for the Carrier C4850C50AJ02061 packaged unit. It converts 120V line voltage to the 24V AC signal that powers your thermostat, contactor coil, gas valve, and every other component in the low-voltage control circuit. When the transformer fails, the entire system goes silent — no thermostat response, no fan, no heat or cooling — because every control signal originates from this single component. A failed transformer is often caused by a short in the low-voltage wiring or a faulty control board drawing excess current; always inspect the secondary circuit before installing a replacement.

• Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | Replaces OEM part# HT01BD236 | Factory-matched mounting footprint and lead configuration
• OEM vs Generic: This OEM unit is wound to exact factory VA and voltage tolerances. Undersized or off-tolerance generic transformers can overheat, trip their internal thermal fuse prematurely, or fail to sustain voltage under full control-circuit load — leading to nuisance lockouts and repeat failures.
• Install difficulty: 2/5 — Disconnect power at the breaker and confirm voltage is absent before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Label or photograph all wiring connections before removing the old transformer. Check secondary wiring for shorts before energizing the new unit.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier C4850C50AJ02061 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate or wiring diagram before ordering. Need fitment confirmation? Our HVAC parts specialists verify compatibility before your order ships — call or chat today.