OEM Carrier 40VA Control Transformer 120V/24V for Model PG8JEB042045AAJA

This OEM step-down transformer is the factory-specified replacement for the Carrier PG8JEB042045AAJA gas furnace. The transformer converts 120V line voltage to the 24V used by your furnace's control circuit — powering the thermostat, gas valve, inducer relay, and all safety controls. When this part fails, the entire control circuit goes dark: the thermostat gets no signal, the inducer never starts, and the furnace produces a complete no-heat condition. It is one of the first components to check when nothing responds at the thermostat.

• Specs: 40VA rating | 120V primary | 24V secondary | 60Hz | Replaces OEM part 322666-701 (superseded by HT680054) | Class 2 listed
• OEM vs Generic: OEM transformers are wound to exact VA and voltage tolerances, preventing brownout dropout and nuisance tripping of downstream safety controls. Generic transformers with loose ±10% tolerances can starve the gas valve solenoid under load.
• Install difficulty: 2/5 — Shut off power at the disconnect and breaker before touching any wiring. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter (to verify 24V output after install). Always photograph the existing wiring before disconnecting. Mount the transformer to the furnace cabinet, reconnect primary and secondary leads, and restore power.
• Warranty: 1-year OEM factory warranty. Ships same business day from our warehouse.

Compatibility: Direct OEM replacement for Carrier model PG8JEB042045AAJA gas furnace. Supersedes legacy part number 322666-701. Verify primary voltage (120V) and VA rating on your unit's data plate before ordering. Need fitment confirmation? Our HVAC parts specialists verify compatibility before you buy — order with confidence and get same-day shipping.