ICP 40VA Transformer for WFSR100C042A2 — 120V to 24V OEM 1177217 | Ships Today

Overview

This OEM 40VA control transformer (part 1177217) supplies low-voltage power for the ICP Tempstar/Heil WFSR100C042A2 furnace. It steps the 120V line voltage down to the 24V control circuit that runs the thermostat, gas valve, control board relays, and contactors. Rated at 40VA, it delivers ample capacity for the unit's control loads. A failed transformer is a common no-power complaint — when it opens, the thermostat goes dark and nothing in the 24V circuit responds. Replacing it with the correct OEM 120V-to-24V unit restores control power and reliable operation.

Specifications

Compatibility

Directly fits the ICP Tempstar/Heil WFSR100C042A2 and other ICP-family units calling for a 40VA 120/24V control transformer. Confirm primary voltage and VA rating before ordering.

Installation Guide

1. Safety First — Disconnect power and verify zero voltage at the transformer with a multimeter.
2. Access — Remove the control/electrical service panel.
3. Document — Photograph the primary (line) and secondary (24V) wiring before disconnecting.
4. Remove — Label and disconnect the leads, then unbolt the old transformer from its mount.
5. Install — Mount the new transformer, reconnect 120V to the primary and 24V to the secondary exactly per the photo.
6. Test — Restore power and confirm 24V at the secondary and normal thermostat/control response.

Signs You Need a Replacement

• Thermostat is blank and the 24V circuit is dead.
• No 24V output measured at the secondary with line power present.
• Burnt smell or visible scorching on the transformer.
• Repeated blown low-voltage fuses or intermittent control dropout.

Shipping & Returns

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