OEM Carrier 40VA Control Transformer 120V/24V for Model PG9MAA036080ABKA (HT01BC116 / HT680054)

This OEM control transformer is the factory-specified replacement for the Carrier PG9MAA036080ABKA gas furnace. The transformer is the heartbeat of your furnace's low-voltage control circuit — it steps down the 120V line voltage to the 24V AC signal that powers your thermostat, control board, gas valve, and all low-voltage accessories. When this part fails, nothing in the system responds: the thermostat goes blank, the furnace won't call for heat, and no error codes display because the board itself has lost power. A failed transformer is one of the most overlooked causes of a completely unresponsive furnace.

• Specs: 40VA rating | 120V AC primary | 24V AC secondary | 60Hz | Foot-mount configuration | Wire lead connections with pre-installed insulated female connectors
• OEM vs Generic: This is a genuine OEM Carrier replacement (updated part HT680054 superseding HT01BC116) delivered in a Carrier factory-authorized parts box. Generic transformers frequently suffer from poor VA tolerance and incorrect mounting geometry — one reviewer noted a generic unit would not mount correctly without modification. OEM ensures exact fitment, correct VA output, and full thermostat circuit protection.
• Install Difficulty: 2/5 — Disconnect power at the breaker and verify voltage is absent before touching any wiring. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to confirm 24V output post-install). Photograph all wire connections before removal. The transformer mounts via a foot bracket and connects via wire leads — straightforward for a competent DIYer.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse when ordered before cutoff.

Compatibility: Designed for the Carrier PG9MAA036080ABKA gas furnace. Also cross-references with Bryant and Payne models sharing the same control circuit. OEM part HT01BC116 has been updated by Carrier to successor part number HT680054 — this is the correct current replacement. Verify your existing transformer's VA rating and primary/secondary voltage on the data plate before ordering. Our fitment team is available to confirm compatibility before you buy.