ICP Transformer 40VA for WFAR100C066B2 – 120V to 24V Control Transformer | Ships Today

Overview

This OEM 40VA control transformer (part #1177217) supplies the low-voltage power for the entire 24V control circuit on your ICP WFAR100C066B2 furnace. It steps the incoming 120V line voltage down to the 24V required by the thermostat, gas valve, igniter, and control board. At 40VA the transformer can deliver roughly 1.67 amps on the secondary — ample headroom for standard furnace controls. A failed transformer produces clear symptoms: a dead thermostat, no response on a call for heat, or a furnace that won't start despite having line power. Failures typically come from a secondary short, age, or a power surge that opens the internal fuse link.

Specifications

Compatibility

Designed as a direct OEM replacement for the ICP / Tempstar / Heil WFAR100C066B2 furnace. This 40VA 120-24V transformer is also used across many ICP family gas furnaces and air handlers built on the same control platform. Verify the part number on your existing transformer before ordering.

Installation Guide

1. Safety First – Disconnect power at the furnace switch and breaker, then verify zero voltage with a multimeter before touching any wiring.
2. Access – Remove the furnace control/blower compartment service panel.
3. Document – Photograph all primary (120V) 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 and reconnect the 120V primary and 24V secondary leads exactly per your photo.
6. Test – Restore power, confirm 24V at the secondary with your meter, and run a heat cycle to verify operation.

Signs You Need a Replacement

• Thermostat screen is blank or completely dead
• Furnace does not respond to a call for heat
• No measurable 24V at the transformer secondary
• Repeated blown control fuses or a tripped internal link

Shipping & Returns

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