OEM Carrier Control Transformer 40VA 208/240V to 24V for Model PY3PPA042090NA

This is the factory OEM replacement control transformer for the Carrier PY3PPA042090NA packaged unit. The transformer steps down line voltage (208/240V) to the 24V AC signal that powers your thermostat circuit, control board, and all low-voltage safety and switching controls. When this part fails, the entire control circuit goes dark — thermostats become unresponsive, contactors won't energize, and the system will not start. A failed transformer is one of the most common causes of a completely non-functional HVAC unit and is one of the first components a technician should check during a no-call diagnostic.

• Specs: OEM Part # HT01BD209 | Input: 208/240V | Output: 24V | Power Rating: 40VA | Frequency: 50/60 Hz | Factory-matched to Carrier PY3PPA042090NA
• OEM vs Generic: OEM transformers are wound to exact factory VA tolerances, protecting sensitive control boards from undervoltage brown-outs. Generic transformers often run at looser tolerances, risking nuisance tripping of the low-voltage fuse or premature board failure.
• Install Difficulty: 2/5 — Shut off all power at the disconnect and breaker before proceeding. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Photograph existing wiring before disconnecting. Verify primary tap selection matches your supply voltage (208V or 240V) before energizing.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse — order by 3 PM for same-day dispatch.

Compatibility: Designed for the Carrier PY3PPA042090NA packaged unit. Always verify your unit's data plate voltage and VA rating before ordering. Not sure if this is the right part? Our HVAC parts specialists verify fitment before you buy — contact us today and we'll confirm compatibility fast.