OEM Carrier 40VA Control Transformer HT01BD236 for Model C4850C50AW04161

This is the OEM factory-specified control transformer for the Carrier C4850C50AW04161 packaged unit. The transformer steps down 120V line voltage to 24V to power the entire control circuit — including the thermostat, contactor coil, and control board. When this part fails, the system goes completely silent: no response from the thermostat, no staging, no fan — nothing works. A failed transformer is one of the most common causes of total system non-response and is often misdiagnosed as a control board failure.

• Specs: OEM Part No. HT01BD236 | Primary: 120V | Secondary: 24V | 40VA rated | Designed for Carrier packaged unit control circuits
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances required by the C4850C50AW04161 control board. Undersized or off-tolerance generic units can overheat, blow fuses repeatedly, or damage downstream control components.
• Install difficulty: 2/5 — Disconnect power at the disconnect box before starting. Tools needed: flathead and Phillips screwdrivers, multimeter (to confirm 24V output after install), wire nuts or spade connectors. Photograph existing wiring before removal. Verify fuse integrity before condemning the transformer.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our HVAC parts warehouse.

Compatibility: Direct OEM replacement for Carrier model C4850C50AW04161 packaged units. Confirm your existing transformer's primary/secondary voltage and VA rating on the unit data plate before ordering. If your system is blowing 24V fuses repeatedly, test the transformer secondary under load with a multimeter — a reading significantly below 24V confirms transformer failure. Our fitment team is available to verify compatibility before you order.