OEM Carrier Control Transformer 40VA 208/240V to 24V for Model PY3PPA042090AA

This genuine OEM control transformer (part #HT01BD209) is the factory-specified replacement for the Carrier PY3PPA042090AA packaged gas/electric unit. The transformer steps down 208/240V line voltage to the 24V signal that powers your thermostat, control board, gas valve, and all low-voltage HVAC controls. When the transformer fails, the entire control circuit goes dead — the system won't respond to the thermostat, won't fire the burner, and won't run the blower. A simple multimeter check across the secondary terminals (expect ~24V AC) confirms failure in seconds.

• Specs: 40VA capacity | 208/240V primary input | 24V AC secondary output | 50/60Hz | Class 2 control transformer | Weight approx. 1.32 lbs
• OEM vs Generic: This is a genuine Carrier OEM part, manufactured to exact factory tolerances. Generic transformers often run hot or output unstable voltage, causing nuisance lockouts and premature control board failure. OEM ensures your low-voltage circuit stays clean and stable.
• Install difficulty: 2/5 — Shut off all power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, wire nuts or spade connectors, multimeter to verify 24V output after install. Always photograph or label existing wiring color codes before disconnecting. Replaces legacy part numbers HT01BD207 and HT01CN232.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY3PPA042090AA packaged unit. Cross-references: HT01BD207, HT01CN232, 9076-00, and 4000A46E07AE28. Verify primary voltage on your unit's data plate (208V or 240V) before ordering — this transformer supports both. Questions about fitment? Our HVAC parts specialists verify compatibility before you order. In stock — ships today.