OEM Carrier Transformer 120V–24V 40VA for Model PY3PPA042060NB

This OEM step-down transformer (part number HT01BD209) is the factory-specified replacement for the Carrier PY3PPA042060NB packaged heat pump unit. The transformer converts 120V line voltage to 24V AC, powering the entire low-voltage control circuit — including the thermostat, contactor coil, reversing valve, and control board. When this part fails, the result is typically a completely unresponsive system: no thermostat display, no contactor pull-in, and no fan or compressor operation. A blown transformer is often caused by a shorted control wire, a failed solenoid coil, or a wiring fault — always inspect the control circuit before installing a replacement.

• Specs: 120V primary | 24V secondary | 40VA rated | Class 2 transformer | Factory OEM tolerance and insulation rating
• OEM vs Generic: OEM units like HT01BD209 are wound and insulated to Carrier's exact VA rating and thermal specs. Generic transformers frequently run at marginal VA capacity, leading to overheating, nuisance tripping, or premature failure — especially under multi-zone thermostat loads.
• Install difficulty: 2/5 — Disconnect power at the disconnect box and verify voltage is zero with a multimeter before touching any wiring. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter. Photograph all wiring connections before removal. Check low-voltage wiring for shorts before energizing.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Engineered specifically for the Carrier PY3PPA042060NB packaged heat pump. Verify your unit's control circuit voltage (24V) and transformer VA rating on the unit data plate or wiring diagram before ordering. Not sure it fits? Our HVAC parts specialists verify fitment before you buy — contact us before placing your order.