OEM Carrier Control Transformer 40VA 208/240V to 24V — Model PY2PNB042060AB

This OEM Carrier control transformer (part #HT01BD209) is the factory-specified replacement for the Carrier PY2PNB042060AB packaged unit. The transformer steps down 208/240V line voltage to the 24V used by the low-voltage control circuit — powering the thermostat, contactor coils, and control board. When this transformer fails, the entire control circuit goes dead: the thermostat goes blank, the system refuses to respond to any call for heating or cooling, and no fault codes are generated because the board itself has no power.

• Specs: Input (Primary): 208/240V | Output (Secondary): 24V | Frequency: 50/60 Hz | Power Rating: 40VA | Factory OEM part #HT01BD209
• OEM vs Generic: This is the genuine Carrier factory part, wound to exact VA and voltage tolerances. Generic transformers are often undersized in real VA capacity, causing overheating, nuisance tripping of the internal thermal fuse, and premature failure — especially under multi-stage or communicating-system loads.
• Install Difficulty: 2/5 — Shut off all power at the disconnect and breaker before starting. Tools needed: flathead and Phillips screwdrivers, wire stripper, voltage tester, needle-nose pliers. Label or photograph all low-voltage wire connections before removing the old transformer. Always check for a blown 3A or 5A control-circuit fuse — a shorted zone valve or contactor coil is often the root cause of transformer failure.
• Warranty: 1-year OEM manufacturer warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY2PNB042060AB packaged unit. Verify your unit's data plate shows a 208/240V primary control circuit before ordering. Not sure it fits? Our HVAC parts specialists verify fitment before every order — contact us with your model and serial number.