ICP Transformer for WFML090C048B3 — 40VA 120/24V | Ships Today

Overview

This OEM control transformer (part #1177217) steps the 120V line voltage down to 24V to power the entire low-voltage control circuit in your ICP Tempstar Heil WFML090C048B3 furnace — thermostat, gas valve, ignition control, and relays. Rated at 40VA, it delivers the current needed to energize all of those loads simultaneously. When the transformer fails, the furnace becomes completely unresponsive: a blank thermostat, no blower, and no ignition, because the 24V circuit has lost power. Typical causes are a shorted control wire, a stuck relay drawing excess current, or age-related winding failure.

Specifications

Compatibility

Direct OEM fit for the ICP Tempstar Heil WFML090C048B3 furnace. This 40VA 120-to-24V transformer is shared across many ICP-family gas furnaces (Tempstar, Heil, Comfortmaker). Verify the VA rating and primary/secondary voltages against your existing transformer before ordering.

Installation Guide

1. Safety First — Disconnect power at the furnace switch and breaker; verify zero voltage with a multimeter before touching any wiring.
2. Access — Remove the furnace control/blower service panel.
3. Document — Photograph all primary (line) and secondary (24V) wire connections before disconnecting.
4. Remove — Disconnect the line and low-voltage leads, then unbolt the failed transformer from its mounting bracket.
5. Install — Mount the new transformer, reconnect primary and secondary leads exactly per your photo, and secure every terminal.
6. Test — Restore power and confirm 24V across the secondary terminals and a normal thermostat startup.

Signs You Need a Replacement

• Thermostat is blank or dead with no 24V at the control board.
• Furnace will not respond to any call for heat.
• Repeatedly blown low-voltage fuse on the control board.
• No measurable 24V output across the secondary terminals.

Shipping & Returns

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