OEM Carrier 40VA Transformer 120V-24V for Model PG9MAA036080AEKA — Part HT01BC116 / HT680054

This OEM control circuit transformer is the factory-specified replacement for the Carrier PG9MAA036080AEKA gas furnace. The transformer steps down 120V line voltage to 24V AC, powering every low-voltage component in the system — thermostat, gas valve, inducer relay, and control board. When it fails, the result is total silence: no thermostat response, no ignition attempt, and no blower activity. A blown fuse, a shorted low-voltage wire, or age-related coil degradation are the most common causes of transformer failure.

• Specs: 40VA rated | 120V AC primary | 24V AC secondary | 60 Hz | Foot-mount configuration | Wire lead connections with insulated female connectors
• OEM vs Generic: This is a factory-authorized OEM replacement (current shipping part HT680054, superseding HT01BC116). OEM transformers maintain precise voltage regulation under load. Generic units often deliver unstable secondary voltage, causing erratic board behavior and nuisance lockouts.
• Install difficulty: 2/5 — Shut off power at the breaker before beginning. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Photograph all wiring connections before removing the old transformer. Check for shorted low-voltage wiring before energizing — a wiring short is the leading cause of repeat transformer failure.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse. Supersedes: HT01BC116, HT01BC116B, HT01BC115, HT01BB126, HT01CT120, HT01BC120, 322666-701, 322953-302, B1810113.

Compatibility: Direct OEM fit for the Carrier PG9MAA036080AEKA gas furnace. Also compatible with a wide range of Carrier, Bryant, and Payne furnaces using the 120V-24V 40VA transformer specification — verify your existing transformer's voltage and VA rating on the data plate before ordering. Questions about fitment? Our HVAC parts specialists verify compatibility before you buy.