OEM Carrier 40VA Furnace Control Transformer 120V–24V for Model PG9MAB036040ABSA

This OEM control transformer is the factory-specified replacement for the Carrier PG9MAB036040ABSA gas furnace. The transformer steps down 120V line voltage to the 24V AC signal that powers your thermostat, control board, gas valve, and all low-voltage safety circuits. When it fails, the entire control circuit goes dead — the furnace will not respond to the thermostat, will not attempt ignition, and no indicator lights will illuminate. A failed transformer is one of the most commonly misdiagnosed furnace faults; always verify with a multimeter before replacing a control board.

• Specs: 40VA rating | 120V primary | 24V secondary | 50/60 Hz single-phase | Wire-lead connections | OEM part number HT01BC116 (superseded by HT680054)
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances for Carrier equipment. Undersized or off-tolerance generic units can cause erratic thermostat behavior, nuisance lockouts, and premature control board failure.
• Install difficulty: 2/5 — Shut off power at the breaker and confirm zero voltage before touching any wiring. Tools needed: multimeter, flat-head screwdriver, needle-nose pliers. Label or photograph all wire connections before disconnecting the old unit. Total replacement time is typically 15–20 minutes.
• Warranty: 1-year OEM manufacturer warranty. In stock — ships same business day when ordered by 3 PM local time.

Compatibility: Factory-matched for Carrier model PG9MAB036040ABSA gas furnace. Also replaces legacy part numbers HT01BC115, HT01BB126, HT01CT120, HT01BC120, HT01AW115, and HT01AA012 across the Carrier, Bryant, and Payne furnace families. Confirm your existing transformer's VA rating and primary/secondary voltage on the data plate before ordering. Our fitment team is available to verify compatibility before you buy.