OEM Carrier Control Transformer 40VA for Model PY4GEWB48090AA

This OEM replacement transformer (part number HT01BC701) is the factory-specified step-down transformer for the Carrier PY4GEWB48090AA packaged gas/electric unit. The transformer steps down 120V line voltage to the 24V AC signal that powers the entire low-voltage control circuit — including the thermostat, control board, contactor coils, and gas valve. When this part fails, the entire control circuit goes dead: the thermostat loses communication, the unit won't respond to any call for heating or cooling, and you may find a blown fuse on the control board as a secondary symptom.

• Specs: 120V primary | 24V secondary | 40VA rated | Factory-matched OEM replacement for Carrier part HT01BC701
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances for the Carrier control board. Under-rated or off-tolerance generic transformers can overheat, trip thermal protection, or cause erratic board behavior and nuisance lockouts.
• Install Difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flat-head and Phillips screwdrivers, multimeter (verify 24V output after install). Always photograph or label existing wiring before disconnecting terminals. Replace any blown 3A control fuse at the same time.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Engineered specifically for the Carrier PY4GEWB48090AA 4-ton 90,000 BTU packaged gas/electric unit. Verify your existing transformer's primary voltage (120V) and VA rating against your unit's data plate before ordering. Our parts specialists are available to confirm fitment before you buy — contact us anytime.