OEM Carrier Control Transformer 208/230V–24V 40VA for Model PF4MNB031T00AAAA

This is the genuine OEM replacement control transformer for the Carrier PF4MNB031T00AAAA fan coil and air handler unit. The transformer steps down line voltage (208/230V primary) to the 24V AC signal that powers your thermostat, control board, relays, and zone valves. When this transformer fails, the entire control circuit goes dead — your thermostat goes blank, the system stops responding to calls for heating or cooling, and no error codes are generated because the board itself has no power. Replacing it with the correct OEM unit restores full system operation immediately.

• Specs: 208/230V primary | 24V secondary | 40VA rated | OEM Part # HT01CN241 | Direct factory drop-in replacement
• OEM vs Generic: This is a genuine Carrier Factory Authorized Part built to exact output voltage and VA tolerances. Undersized or off-spec aftermarket transformers can starve the control board under load, causing erratic lockouts and premature board failure.
• Install difficulty: 2/5 — Shut off power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, multimeter (to confirm 24V output after install), wire nuts or spade connectors. Label all low-voltage wires before disconnecting. Verify 24VAC output with a meter before closing the unit.
• Warranty: 1-year OEM manufacturer warranty. In-stock units ship same business day from our warehouse when ordered by cutoff time.

Compatibility: Designed as the factory-specified replacement for the Carrier PF4MNB031T00AAAA fan coil/air handler. Confirm your existing transformer's primary voltage (208V or 230V) and VA rating on the data plate before ordering. Need fitment verification? Our HVAC parts specialists confirm compatibility before you buy — no guesswork required.