OEM Carrier Control Transformer 40VA 208/240V to 24V for Model PY1PPB042090AAAA

This OEM control transformer (part# HT01BD209) is the factory-specified replacement for the Carrier PY1PPB042090AAAA packaged unit. The transformer steps down 208/240V line voltage to the 24V DC used by the thermostat, control board, contactor coil, and all low-voltage safety circuits. When it fails, the entire control circuit goes dead — the thermostat loses power, the system stops responding to calls for heating or cooling, and no components will energize. It is one of the most common root causes of a completely unresponsive HVAC system.

• Specs: 40VA power rating | 208/240V primary input | 24V secondary output | 50/60Hz | OEM part number HT01BD209 | Factory-matched to Carrier PY1PPB042090AAAA
• OEM vs Generic: This is a genuine Carrier OEM transformer wound to exact factory VA tolerances. Undersized or out-of-spec aftermarket transformers can overheat under full control-circuit load, tripping thermal protection and causing intermittent lockouts.
• Install difficulty: 2/5 — Shut off all power at the breaker and disconnect switch before starting. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, wire nuts or terminal connectors, multimeter. Always photograph or label existing wiring before disconnecting. Verify 24V output with a multimeter after installation before reassembling the cabinet.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY1PPB042090AAAA packaged unit. Cross-references include HT01CN232 and HT01CN233. Verify your unit's control voltage and VA requirement on the data plate before ordering. Our team is available to confirm fitment — order with confidence and get your system back up today.