OEM Carrier Control Circuit Transformer 40VA for Model C48A505064

This is the factory OEM replacement transformer (part number HT01BD702) for the Carrier C48A505064 packaged unit. The transformer steps down 120V line voltage to the 24V signal that powers your control board, thermostat, and all low-voltage safety circuits. When it fails, every controlled function goes silent — the thermostat goes blank, the unit refuses to respond to any call for heating or cooling, and no error codes will display because the control board itself has lost power. It's often misdiagnosed as a failed control board or thermostat before the transformer is tested.

• Specs: 40VA rated | 120V primary / 24V secondary | Class 2 output | OEM part number HT01BD702 | Factory-matched impedance for stable 24V signal
• OEM vs Generic: OEM transformers are wound to exact VA and impedance specifications for the C48A505064 control circuit. Undersized or off-spec generic units can sag under load, causing intermittent lockouts, nuisance trips, or premature secondary fuse failures.
• Install difficulty: 2/5 — Disconnect power at the disconnect box before starting. Tools needed: flathead and Phillips screwdrivers, multimeter (to verify 24V output before closing the panel), wire nuts or spade connectors. Photograph or label all wiring before removal. Confirm the 24V secondary fuse or board-mounted fuse is intact before replacing the transformer.
• Warranty: 1-year OEM factory warranty. In-stock and ships the same business day from our climate-controlled warehouse.

Compatibility: Engineered specifically for the Carrier C48A505064 packaged unit. Verify your existing transformer's VA rating, primary voltage, and secondary voltage on the unit data plate or transformer housing before ordering. If you're unsure, our parts specialists confirm fitment at no charge — just reach out before you buy. Order today and receive same-day shipping on all in-stock OEM parts.