ICP Transformer for WFML135D066A1 — 40VA 120/24V | Ships Today

Overview

This is a genuine OEM control transformer (part number 1176944) for the ICP Tempstar Heil WFML135D066A1 gas furnace. The transformer steps down incoming 120V line voltage to the 24V control voltage that powers your thermostat, gas valve, ignition control board, and relays. Rated at 40VA, it supplies the low-voltage current the entire control circuit depends on. When a transformer fails, the furnace goes completely dead on the control side — no thermostat display, no call for heat, no blower, and often a blown low-voltage fuse on the control board. A buzzing, overheated, or visibly scorched transformer is a sure sign of failure.

Specifications

Compatibility

Engineered as a direct OEM fit for the ICP Tempstar Heil WFML135D066A1 furnace and shared across many ICP-family gas furnaces using a 40VA 120V-to-24V control transformer. Always confirm your existing transformer is rated 120V primary / 24V secondary at 40VA before installing.

Installation Guide

1. Safety First — Disconnect power at the furnace switch and breaker, then verify zero voltage with a multimeter.
2. Access — Remove the furnace control/blower service panel.
3. Document — Photograph all primary and secondary wire connections before disconnecting.
4. Remove — Disconnect the line-voltage primary leads and 24V secondary leads, then unbolt the transformer from its mounting bracket.
5. Install — Mount the new transformer, reconnect primary and secondary leads exactly per your photo.
6. Test — Restore power, confirm 24V across the secondary, and verify the thermostat calls for heat normally.

Signs You Need a Replacement

• Furnace completely unresponsive — no thermostat power or display
• Repeatedly blown low-voltage fuse on the control board
• Audible buzzing or humming from the transformer
• Burnt smell, discoloration, or melted housing

Shipping & Returns

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