OEM Carrier 40VA Control Transformer for Model C4850C48ZG060900

This is the OEM factory-specified control transformer (part# HT01BD236) for the Carrier C4850C48ZG060900 packaged unit. The transformer steps down 120V line voltage to 24V to power the entire low-voltage control circuit — including the thermostat, contactor coil, gas valve, and control board. When this transformer fails, absolutely nothing in the control system responds: the thermostat goes blank, the unit won't call for heating or cooling, and you may measure zero voltage on the 24V secondary terminals. It is one of the first components to check in a completely unresponsive HVAC system.

• Specs: 40VA rated | 120V primary / 24V secondary | OEM part number HT01BD236 | Direct drop-in replacement with factory-matched wire leads and mounting footprint
• OEM vs Generic: The OEM HT01BD236 transformer is wound to exact Carrier VA and voltage tolerances, ensuring stable 24V output under full control circuit load. Generic transformers often run under-rated VA, causing voltage sag that triggers nuisance lockouts or premature contactor coil failure.
• Install difficulty: 2/5 — Disconnect power at the disconnect box before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Label or photograph existing wire connections before removing the old unit. Check for a shorted secondary circuit before installing the new transformer — a shorted control wire will immediately blow the new unit.
• Warranty: 1-year OEM factory warranty. Orders placed before 3 PM ship the same business day from our warehouse.

Compatibility: Designed for the Carrier C4850C48ZG060900 packaged unit. Always verify primary voltage (120V) and VA rating on your unit's data plate before ordering. If you are unsure of fitment, our HVAC parts specialists are available to confirm compatibility before you buy — no guesswork required.