ICP Transformer for WFMR090B042B2 — 40VA 120/24V | Ships Today
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Overview
This OEM 40VA step-down transformer (OEM 1177217) supplies the 24-volt control power for the ICP/Tempstar/Heil WFMR090B042B2 furnace. It converts incoming 120V line voltage to the 24V that runs the thermostat, control board, gas valve, and relays. When a transformer fails — often from a shorted control wire or stuck contactor — the entire low-voltage circuit goes dead: the thermostat is blank, the furnace won't start, and nothing responds to a heat call. A 40VA rating provides enough capacity for the furnace's control load with margin. Replacing a blown transformer restores 24V power and brings the control system back online.
Specifications
| Spec | Value |
|---|---|
| OEM Part Number | 1177217 |
| Type | Step-Down Control Transformer |
| Rating | 40 VA |
| Voltage | 120V Primary / 24V Secondary |
| Brand | ICP / Tempstar / Heil |
| Fits Model | WFMR090B042B2 |
| Application | Furnace 24V Control Circuit |
Compatibility
Designed for the ICP-family WFMR090B042B2 furnace and interchangeable across the Tempstar, Heil, and Comfortmaker models that use a 40VA 120-24V control transformer. Confirm the primary/secondary voltages and VA rating against your existing transformer before installing.
Installation Guide
- Safety First — Disconnect power at the furnace switch and breaker; verify zero voltage with a multimeter.
- Access — Remove the furnace control-compartment service panel.
- Document — Photograph the primary (line) and secondary (24V) wiring before disconnecting.
- Remove — Disconnect the leads, remove the transformer mounting screws, and lift out the failed unit.
- Install — Mount the new transformer, connect 120V to the primary and 24V to the secondary per your photo, and check for any shorted control wire that caused the original failure.
- Test — Restore power and confirm 24V across the secondary, then verify the thermostat and furnace respond to a heat call.
Signs You Need a Replacement
- Blank thermostat and dead low-voltage controls
- Furnace gets line power but won't start
- No 24V reading across the transformer secondary
- Transformer is hot, buzzing, or smells burnt
Shipping & Returns
Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.
Shipping Information
- Orders placed before 3PM CST ship same business day
- Standard delivery: 2-5 business days
- Express shipping available at checkout
- Free shipping on orders over $75
- Tracking number emailed upon shipment
Return Policy
- 30-day returns on unused parts in original packaging
- Electrical parts (capacitors, contactors, control boards) are final sale once installed
- Email info@nationalhvacparts.com to initiate a return
- Refunds processed within 5-7 business days