ICP 40VA Transformer for X8MPT125J20A1 — 115V to 24V OEM Control Transformer | Ships Today

Overview

This OEM control transformer (part #1012722) steps your incoming 115V line voltage down to the 24V control voltage that runs the thermostat, gas valve, control board relays, and safety circuits on your ICP / Tempstar / Heil X8MPT125J20A1 furnace. Rated at 40VA, it supplies enough current for the full low-voltage load of a two-stage furnace plus a typical thermostat and condensing unit contactor. When a transformer fails — usually from a shorted thermostat wire, a stuck contactor drawing excess current, or simple age — the entire 24V control system goes dead: no display on the thermostat, no response to a heat or cool call, and no clicking from the gas valve or relays. This direct-fit OEM transformer restores 24V control power without the guesswork of universal substitutes.

Specifications

Compatibility

Built for the ICP-family X8MPT125J20A1 two-stage furnace and the matching Tempstar, Heil, Comfortmaker, and Day & Night control systems that use a 115V-to-24V 40VA transformer. Verify your primary line voltage is 115V and that your existing transformer is rated 40VA before ordering.

Installation Guide

1. Safety First — Disconnect power at the breaker and verify zero voltage with a multimeter at both the line and control terminals.
2. Access — Remove the furnace control-compartment service panel to expose the transformer and control board.
3. Document — Photograph every primary (line) and secondary (24V) lead and terminal before disconnecting.
4. Remove — Label and disconnect the primary and secondary leads, then unbolt the transformer from its mounting bracket.
5. Install — Mount the new transformer, reconnect the 115V leads to the primary and the 24V leads to the secondary exactly per your photo.
6. Test — Restore power and confirm 24VAC across the secondary terminals, then run a heat and cool call to verify the thermostat and controls respond.

Signs You Need a Replacement

• Thermostat screen is blank and the furnace won't respond to any call.
• No 24VAC reading across the transformer secondary terminals.
• Burnt smell or visibly scorched/melted transformer housing.
• Blown low-voltage fuse on the control board that re-blows immediately.

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 — if it doesn't fit your X8MPT125J20A1, we make it right.