ICP Transformer 40VA 120/24V for WFMR135D066B1 — OEM 1177217 | Ships Today

Overview

This is a genuine OEM 40VA control transformer (OEM part #1177217) for the ICP Tempstar Heil WFMR135D066B1 furnace. The transformer steps down 120V line voltage to the 24V low-voltage control circuit that powers your thermostat, gas valve, control board, and relays. When a transformer fails, the entire low-voltage control system goes dead — the thermostat screen goes blank, the blower and burners won't fire, and the unit appears completely unresponsive even though line power is present. A failed transformer is one of the most common causes of a furnace that has "no power" despite the breaker being on.

Specifications

Compatibility

Engineered as a direct-fit replacement for the ICP Tempstar Heil WFMR135D066B1. ICP-built 40VA 120/24V transformers are also used across many Comfortmaker, Heil, and Tempstar gas furnace platforms — always confirm your existing transformer is rated 120V primary / 24V secondary at 40VA before installing.

Installation Guide

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

Signs You Need a Replacement

• Blank thermostat and completely dead low-voltage controls
• No 24V reading across the secondary terminals
• Repeated blown control-board or transformer fuses
• Burnt smell or visible scorching on the transformer body

Shipping & Returns

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