Tempstar 40VA Transformer for TDE075B12G1 — 115V to 24V | Ships Today

Overview

This OEM 40VA control transformer (part number 1012722) steps line voltage down from 115V to the 24V low-voltage power used by the Tempstar TDE075B12G1 furnace control board, gas valve, thermostat, and ignition circuit. Without a working transformer the furnace has no control power: the thermostat goes dark, the control board won't energize, and the system will not start. Transformers fail from age, overloading a shorted low-voltage circuit, or power surges — often the primary or secondary winding opens or the unit overheats.

Specifications

Compatibility

Direct-fit OEM replacement for the Tempstar TDE075B12G1 furnace. Because ICP builds Tempstar, Heil, and Comfortmaker furnaces on common platforms, this 40VA 115V-to-24V transformer also serves equivalent ICP-family units that call out part 1012722. Verify against your unit's wiring diagram before installing.

Installation Guide

1. Safety First — Disconnect electrical power to the furnace and verify zero voltage with a multimeter.
2. Access — Remove the furnace control-compartment service panel.
3. Document — Photograph all primary (line) and secondary (24V) wire connections before disconnecting.
4. Remove — Disconnect the wiring, remove the transformer mounting screws, and lift out the old transformer.
5. Install — Mount the new transformer, then reconnect the 115V primary and 24V secondary leads exactly as photographed.
6. Test — Restore power, confirm 24V at the secondary, and verify the thermostat and furnace power up normally.

Signs You Need a Replacement

• Thermostat screen is blank and furnace is completely unresponsive
• No 24V present at the control board secondary
• Repeated blown low-voltage fuse after a short is cleared
• Transformer is hot to the touch, buzzing, or shows burnt/melted windings

Shipping & Returns

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