Tempstar 40VA Transformer for T9MVX060F12A1 — 115V to 24V Primary | Ships Today

Overview

This OEM 40VA control transformer (part #1172810) supplies low-voltage power to the controls of your Tempstar T9MVX060F12A1 gas furnace. It steps the incoming 115V line voltage down to the 24V required by the control board, gas valve, igniter circuit, and thermostat. When a transformer fails, the entire 24V control circuit goes dead — the furnace will not respond to a thermostat call, the control board shows no power, and nothing energizes. Rated at 40VA, it provides enough capacity to drive the furnace's electronic ignition controls plus the thermostat load without overheating.

Specifications

Compatibility

Direct OEM fit for the Tempstar T9MVX060F12A1 variable-speed gas furnace. The same 1172810 transformer is shared across many ICP-family furnaces sold under the Tempstar, Heil, Comfortmaker, and Arcoaire brands. Always confirm the printed part number on your existing transformer before ordering.

Installation Guide

1. Safety First — Disconnect power at the furnace switch and breaker, then verify zero voltage at the transformer terminals with a multimeter.
2. Access — Remove the furnace control/burner service panel.
3. Document — Photograph all primary (line) and secondary (24V) wire connections before disconnecting.
4. Remove — Disconnect the primary and secondary leads, then unbolt the transformer from its mounting bracket.
5. Install — Mount the new transformer, reconnect the 115V primary and 24V secondary leads exactly per your photo.
6. Test — Restore power and confirm 24V at the secondary and a normal ignition sequence on a thermostat call.

Signs You Need a Replacement

• Furnace completely unresponsive to the thermostat with no 24V control power
• Repeatedly blown low-voltage fuse on the control board
• Buzzing, humming, or scorched/burnt smell from the transformer
• Measured 0V or incorrect voltage on the secondary side with 115V present on the primary

Shipping & Returns

Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.