OEM Carrier 40VA Control Transformer HT01BD209 for Model PY3PNA030040NB

This OEM Carrier control transformer (part #HT01BD209) is the factory-specified replacement for the Carrier PY3PNA030040NB packaged unit. The transformer steps down the 208/240V line voltage to the 24V signal required to power the entire low-voltage control circuit — including the thermostat, contactor coil, gas valve, and control board. When this part fails, the system goes completely unresponsive: no thermostat communication, no staging, no heat or cool. A failed transformer is one of the most common causes of a fully dead HVAC system.

• Specs: 208/240V primary input | 24V secondary output | 40VA power rating | 50/60 Hz | Factory-matched OEM tolerances for the PY3PNA030040NB control circuit
• OEM vs Generic: The OEM HT01BD209 is wound to Carrier's exact VA rating and insulation class. Generic transformers frequently run under-rated VA, leading to overheating and premature failure under full control-load conditions.
• Install difficulty: 2/5 — De-energize and lock out power before starting. Tools needed: multimeter, flathead/Phillips screwdrivers, wire stripper, needle-nose pliers. Photograph or label all 24V wiring before disconnecting terminals. Verify primary voltage tap matches your supply voltage before powering up.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY3PNA030040NB packaged unit. Verify your unit's supply voltage (208V or 240V) against the transformer's primary tap before installation. Cross-references include HT01CN232 and HT01CN233. Questions about fitment? Our HVAC parts specialists confirm compatibility before you order — ships same day.