Tempstar 40VA Transformer for T8MPL075B12A1 — 115V to 24V Control | Ships Today

Overview

This OEM control transformer (part number 1012722) steps 115V line voltage down to 24V to power the low-voltage control circuit of the Tempstar T8MPL075B12A1 gas furnace. Rated at 40VA, it supplies the thermostat, gas valve, control board, and relays. When a transformer fails — often from a shorted gas valve or thermostat wire — the furnace goes completely dead with no thermostat display, no inducer, and no response to a call for heat. Replacing it with a correctly rated 40VA OEM unit restores reliable control power across the heating system.

Specifications

Compatibility

Direct OEM replacement for the Tempstar T8MPL075B12A1 furnace and shared across many ICP/Heil/Comfortmaker single-stage furnaces using the 1012722 40VA transformer. Confirm primary/secondary voltages and VA rating before ordering.

Installation Guide

1. Safety First — Disconnect power at the switch and breaker, and verify zero voltage with a multimeter.
2. Access — Remove the control/service panel to locate the transformer near the control board.
3. Document — Photograph all primary and secondary wire connections before disconnecting.
4. Remove — Label and disconnect the leads, then unbolt the old transformer from its bracket.
5. Install — Mount the new 40VA transformer and reconnect the 115V primary and 24V secondary leads per your photo.
6. Test — Restore power, confirm 24V at the secondary, and run a heat cycle to verify control operation.

Signs You Need a Replacement

• Furnace and thermostat completely unpowered (no 24V).
• Blown low-voltage fuse on the control board that re-blows.
• Burning smell or visibly scorched transformer.
• No response to a call for heat despite good line voltage.

Shipping & Returns

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