OEM Carrier 40VA Control Transformer 208/240V to 24V — HT01BD209 for Model PY2PPB030040AA

The Carrier HT01BD209 is the factory OEM control transformer for the PY2PPB030040AA packaged unit. Its job is critical and simple: step down 208/240V line voltage to the 24V signal voltage that powers your thermostat, control board, contactor coil, and every other low-voltage component in the system. When this transformer fails, the entire control circuit goes dark — the thermostat displays nothing, the system won't call for heating or cooling, and no components respond at all. A failed transformer is often misdiagnosed as a bad thermostat or control board; always test transformer output voltage first.

• Specs: Input 208/240V AC | Output 24V AC | Power Rating 40VA | Frequency 50/60Hz | OEM Part # HT01BD209 | Replaces HT01CN232
• OEM vs Generic: This is the genuine Carrier factory part, wound to exact VA tolerances. Generic transformers frequently run hot under full load and can damage downstream 24V components — particularly sensitive control boards — if their output voltage drifts.
• Install difficulty: 2/5 — Shut off all power at the disconnect and breaker before starting. Tools needed: multimeter, flathead and Phillips screwdrivers, wire stripper, electrical tape. Photograph all wiring connections before disconnecting. Confirm 24V output with a multimeter after installation before restoring full power.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY2PPB030040AA packaged unit. This transformer also fits a broad range of Carrier, Bryant, and Payne residential and commercial HVAC systems requiring a 208/240V-primary, 24V-secondary, 40VA control transformer — verify your unit's data plate before ordering. Need fitment confirmation? Our HVAC parts specialists verify compatibility before you buy.