OEM Carrier 40VA Control Transformer 120V–24V for Model PG9MAA024040ACKA

This OEM control transformer (part number HT01BC116, superseded by HT680054) is the factory-specified replacement for the Carrier PG9MAA024040ACKA gas furnace. The transformer steps down 120V line voltage to 24V to power the entire low-voltage control circuit — including the thermostat, gas valve, inducer relay, and ignition board. When this transformer fails, the furnace goes completely silent: no thermostat response, no inducer startup, no ignition attempt. If you're measuring 120V at the primary but zero volts at the secondary, this transformer is almost certainly the culprit.

• Specs: 120 VAC primary | 24 VAC secondary | 40 VA rating | 50/60 Hz | Single phase | Wire lead connections | Factory-matched to Carrier PG9MAA024040ACKA
• OEM vs Generic: OEM transformers are wound to exact factory VA tolerances, protecting downstream components like control boards and gas valves from voltage fluctuations. Generic units often run outside VA spec, risking nuisance lockouts or premature board failure.
• Install difficulty: 2/5 — Turn off the 120V disconnect and confirm zero voltage with a multimeter before touching wiring. Tools needed: flathead and Phillips screwdrivers, multimeter, wire nuts or quick-disconnect terminals. Photograph existing wiring connections before removal. Note: HT01BC116 is superseded by OEM part HT680054 — both are fully compatible.
• Warranty: 1-year OEM factory warranty. In-stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PG9MAA024040ACKA gas furnace. Also compatible with a broad range of Carrier, Bryant, and Payne furnace models that specify a 120V–24V 40VA control transformer. Always verify primary voltage, secondary voltage, and VA rating on your unit's data plate before ordering. Have a fitment question? Our HVAC parts team confirms compatibility before you buy — reach out before you order.