ICP Transformer for WFML135D066B3 — 40VA 120/24V Control Transformer | Ships Today

Overview

This OEM control transformer (part #1177217) converts 120V line voltage to the 24V control voltage that operates your ICP, Tempstar, or Heil furnace. Rated at 40VA, it supplies the thermostat circuit, ignition control board, gas valve, and blower relays. When the transformer fails, the low-voltage control system shuts down completely — the thermostat goes dark, no heat or cool call is honored, and the blower stays off. A repeatedly blown low-voltage fuse, an audible buzz, or a scorched smell at the control box indicates an overloaded or internally shorted transformer. This factory-spec 40VA 120/24V unit is a direct drop-in replacement.

Specifications

Compatibility

Fits ICP model WFML135D066B3 and related Tempstar, Heil, and Comfortmaker furnaces that use a 40VA 120/24V control transformer. Confirm the primary voltage tap and VA rating against the failed unit before installing.

Installation Guide

1. Safety First — Disconnect power at the breaker and verify zero voltage with a multimeter.
2. Access — Remove the furnace service panel.
3. Document — Photograph the primary and secondary wiring before disconnecting.
4. Remove — Disconnect the line and 24V leads, then unbolt the old transformer from the control panel.
5. Install — Mount the new transformer, reconnect leads exactly per your photo, and verify the correct primary tap.
6. Test — Restore power and confirm 24V across the secondary terminals and normal furnace control response.

Signs You Need a Replacement

• No 24V output / dead thermostat and controls
• Low-voltage fuse blows repeatedly
• Buzzing or humming from the transformer
• Burnt smell or scorching at the control box

Shipping & Returns

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