ICP Transformer for WFMR045A036B3 — 40VA 120/24V Step-Down | Ships Today

Overview

This OEM 40VA control transformer (part #1177217) steps the incoming 120V line down to 24V to power the thermostat, gas valve, relays, and control board in your ICP/Tempstar/Heil WFMR045A036B3 furnace. When the transformer fails, the entire low-voltage control circuit loses power — the thermostat goes blank, the furnace ignores every call for heat or cool, and the low-voltage fuse may blow. A transformer that buzzes loudly, runs hot, or smells of burnt insulation is failing and should be replaced.

Specifications

Compatibility

Direct OEM fit for the ICP/Tempstar/Heil WFMR045A036B3 furnace. The 40VA 120-24V rating is shared across many ICP-family models — confirm your existing transformer's VA and voltage match before installing.

Installation Guide

1. Safety First — Disconnect power at the breaker and verify zero voltage with a multimeter at the line and control terminals.
2. Access — Remove the furnace service panel to reach the control compartment.
3. Document — Photograph all primary (120V) and secondary (24V) wire connections before disconnecting.
4. Remove — Disconnect the primary and secondary leads and unbolt the failed transformer from its bracket.
5. Install — Mount the new transformer and reconnect the wiring exactly per your photo.
6. Test — Restore power, confirm 24V across the secondary terminals, and verify normal system operation.

Signs You Need a Replacement

• Thermostat is blank with no 24V control power
• Furnace will not respond to any heating or cooling call
• Repeatedly blown 24V control fuse
• Transformer buzzes loudly, runs hot, or smells burnt

Shipping & Returns

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