OEM Carrier 40VA Control Transformer 120V–24V for Model PG8UAA036045ADJA

This OEM control transformer is the factory-specified replacement for the Carrier PG8UAA036045ADJA gas furnace. Part number HT01BC116 (superseded by HT680054) steps down 120V line voltage to 24V AC, powering every low-voltage component in your furnace and air conditioning system — including the thermostat, gas valve, control board, and contactor. When this transformer fails, the entire control circuit goes dead: no thermostat response, no ignition sequence, and no heat. If you're measuring 120V on the primary side but zero volts on the secondary, this transformer is your culprit.

• Specs: 40VA rating | 120V AC primary (110–125V range) | 24V AC secondary | Foot-mount configuration | Wire lead connections | 60 Hz
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances required by Carrier's control boards. Undersized or off-tolerance aftermarket transformers can cause nuisance lockouts, board damage, or premature failure of downstream low-voltage components.
• Install Difficulty: 2/5 — Shut off power at the disconnect and breaker before starting. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to verify 0V before touching leads). Label and photograph all wire connections before removal. Torque terminal screws firmly — loose low-voltage connections are a leading callback cause.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Engineered for Carrier model PG8UAA036045ADJA gas furnaces. Note that OEM part number HT01BC116 has been superseded by HT680054 — both are the same 40VA, 120V–24V transformer. Cross-references include HT01BC115, HT01BC116B, HT01BB126, and HT01BC120. Verify your existing transformer's primary voltage and VA rating against your unit's data plate before ordering. Have a question about fitment? Our team confirms compatibility before you buy — ships same day.