OEM Carrier 40VA Control Transformer 120V–24V for Model PG9MAA024040AEKA

This OEM control transformer (part number HT01BC116 / superseded by HT680054) is the factory-specified replacement for the Carrier PG9MAA024040AEKA gas furnace. The transformer steps down 120V line voltage to 24V AC to power the entire low-voltage control circuit — including the thermostat, gas valve, inducer relay, and control board. When it fails, nothing responds: the thermostat goes dark, the furnace won't call for heat, and diagnostics show no 24V signal at the board. A failed transformer is one of the most misdiagnosed furnace problems, often confused with a bad control board or thermostat.

• Specs: 40VA rated | 120V AC primary | 24V AC secondary | 60 Hz | Foot-mount configuration | Wire lead connections | Replaces HT01BC116, HT01BC116B, HT01BC115, HT01BB126, HT680054
• OEM vs Generic: OEM transformers are wound to exact factory VA and voltage tolerances. Undersized or off-tolerance generic units can cause erratic thermostat behavior, nuisance lockouts, and premature control board failure — costing far more than the part savings.
• Install difficulty: 2/5 — Shut off power at the disconnect and breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (verify 0V before touching terminals). Note wire lead colors and terminal positions before disconnecting the old unit.
• Warranty: 1-year OEM factory warranty against defects. Ships same business day from our warehouse.

Compatibility: Direct OEM fit for Carrier model PG9MAA024040AEKA gas furnace. Note that OEM part number HT01BC116 has been superseded by HT680054 — both are the same factory-spec 40VA 120V/24V transformer. Verify your unit's data plate voltage and VA rating before ordering. Our parts team is available to confirm fitment before you buy.