OEM Carrier 40VA Control Transformer 208/240V to 24V (HT01BD209) for Model PY1PJB048090AAAA

The Carrier HT01BD209 is the factory-specified control transformer for the PY1PJB048090AAAA packaged unit. Its job is to step down the 208/240V line voltage to the 24V signal required by thermostats, control boards, gas valves, and contactors. When this transformer fails, the low-voltage control circuit goes dead — thermostats go blank, the system refuses to start, and no call-for-heat or cool is processed. It is one of the most straightforward and highest-impact components to diagnose and replace in the field.

• Specs: Input 208/240V | Output 24V | 40VA power rating | 50/60Hz | Factory-matched OEM tolerances
• OEM vs Generic: This is the genuine Carrier OEM part (HT01BD209), manufactured to exact VA and voltage tolerances. Off-brand substitutes can run hot, drop voltage under load, or fail prematurely — risking damage to connected control boards and components.
• Install difficulty: 2/5 — Always shut off power at the disconnect before servicing. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter (verify 24V output after install). Label all low-voltage wires before disconnecting from old transformer terminals.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Direct OEM replacement for Carrier model PY1PJB048090AAAA. Verify your unit's data plate shows a 208/240V primary and 24V secondary requirement before ordering. Not sure it's the right part? Our HVAC parts team confirms fitment before you buy — order with confidence.