OEM Carrier 40VA Control Transformer for Model C4850C48ZG070200

This OEM control transformer (part# HT01BD236) is the factory-specified replacement for the Carrier C4850C48ZG070200 packaged unit. The transformer steps down 120V line voltage to the 24V signal voltage required by your thermostat, contactor coil, gas valve, and control board. When this component fails, the entire control circuit goes dead — the thermostat goes blank, the system won't respond to any call for heating or cooling, and no fault codes will display because the board itself has no power. It is often the first component to check when nothing works at all.

• Specs: 40VA rating | 120V primary / 24V secondary | Class 2 output | Compatible with standard residential and light-commercial control circuits | Replaces OEM part number HT01BD236
• OEM vs Generic: This factory OEM transformer is wound to exact VA and voltage tolerances for the Carrier C4850C48ZG070200. Generic transformers frequently under-deliver VA under load, causing intermittent resets, nuisance tripping of the secondary fuse, or premature board failure — false economy that costs more in callbacks.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter (to confirm 24V output after install). Label or photograph all low-voltage wiring before disconnecting. Secondary fuse replacement is recommended at the same time if the transformer failed due to a wiring short.
• Warranty: 1-year OEM factory warranty against defects. Orders placed before 3PM EST ship the same business day from our climate-controlled warehouse.

Compatibility: Designed and factory-matched for the Carrier C4850C48ZG070200 packaged unit. Always verify your existing transformer's VA rating and primary/secondary voltages on the data plate or wiring diagram before ordering. Need fitment confirmed? Our HVAC parts specialists verify compatibility before you buy — contact us anytime.