Tempstar 40VA Transformer for T9MPX060F12A2 — 115V to 24V | Ships Today

Overview

This OEM control transformer (part 1172810) steps line voltage down from 115V to 24V to power the low-voltage control circuit in your Tempstar T9MPX060F12A2 gas furnace. Rated at 40VA, it feeds the thermostat, control board, gas valve, and relays. When the transformer fails — typically from a shorted thermostat wire, a stuck contactor, or age — the whole 24V control system goes dead: no thermostat display, no blower, no heat. Replacing the transformer is the reliable fix when the windings are open or burned.

Specifications

Compatibility

Direct-fit replacement for the Tempstar T9MPX060F12A2 gas furnace. The 1172810 40VA transformer is widely used across ICP, Heil, Comfortmaker, and Carrier-family furnaces and air handlers on the same control platform. Confirm your existing unit is rated 115V primary / 24V secondary at 40VA before installing.

Installation Guide

1. Safety First — Disconnect power at the furnace switch and breaker, then verify zero voltage at the transformer leads with a multimeter.
2. Access — Remove the control compartment service panel.
3. Document — Photograph the primary and secondary wiring before disconnecting.
4. Remove — Label and disconnect the leads, remove the mounting screws, and pull the old transformer.
5. Install — Mount the new transformer and reconnect the 115V primary and 24V secondary leads exactly as documented.
6. Test — Restore power, confirm 24V at the secondary with a meter, and verify the thermostat and control board power up.

Signs You Need a Replacement

• Blank or dead thermostat with good batteries
• No 24V output measured at the secondary terminals
• Burning smell or visibly charred transformer windings
• Furnace completely unresponsive to a heat call

Shipping & Returns

Ships same day on orders placed before 3 PM CST. 30-day hassle-free returns. Backed by the National HVAC Parts fitment guarantee.