ICP 40VA Transformer for WFHR100C048A1 — 120-24V | Ships Today

Overview

This OEM control transformer (part 1177217) is the 40VA, 120V-to-24V step-down transformer for the ICP/Tempstar/Heil WFHR100C048A1 gas furnace. It powers the entire 24V control circuit — thermostat, gas valve, control board logic, and relays. A 40VA rating supplies enough current for the furnace control loads plus a typical thermostat and accessories. When a transformer fails or its internal fuse-link opens (often after a 24V short or a shorted thermostat wire), the furnace goes completely dead with no thermostat response and no 24V at the control board. A buzzing, overheating, or visibly scorched transformer is also a clear sign of failure.

Specifications

Compatibility

Direct-fit replacement for the ICP WFHR100C048A1 furnace and shared-platform Tempstar, Heil, and Comfortmaker models using a 40VA 120/24V control transformer. Verify the VA rating and primary/secondary voltages on your existing transformer before installing.

Installation Guide

1. Safety First — Disconnect power at the furnace switch and breaker, and verify zero voltage with a multimeter.
2. Access — Remove the furnace control compartment service panel.
3. Document — Photograph the primary (line) and secondary (24V) wiring before disconnecting.
4. Remove — Disconnect the leads, remove the mounting screws, and take out the old transformer.
5. Install — Mount the new transformer and reconnect primary and secondary leads exactly per your photo. Correct any shorted 24V wiring that caused the original failure.
6. Test — Restore power and confirm 24V at the secondary and normal furnace operation.

Signs You Need a Replacement

• Furnace dead with no 24V at the control board
• Thermostat blank or unresponsive
• Buzzing or overheating transformer
• Burnt smell or visible scorching at the transformer

Shipping & Returns

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