Tempstar 40VA Transformer for TNE100J20G1 — 115V to 24V | Ships Today
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Overview
This genuine OEM 40VA control transformer (part number 1012722) supplies the low-voltage power for the Tempstar TNE100J20G1 furnace. It steps the 115-volt line input down to the 24-volt secondary that powers the control board, thermostat, gas valve, and relays. Rated at 40VA, it provides enough capacity for the furnace control circuit plus typical accessory loads. When this transformer fails — usually from a shorted secondary, overload, or age — the entire 24V control system goes dead: no thermostat display, no blower or burner response, and no ignition sequence. A buzzing, scorched, or open-winding transformer should be replaced immediately, and the cause of any short corrected before powering the new unit.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1012722 |
| Type | Step-Down Control Transformer |
| Brand | Tempstar (ICP / Heil family) |
| Rating | 40 VA |
| Primary Voltage | 115 V |
| Secondary Voltage | 24 V |
| Fitment | OEM direct replacement |
Compatibility
Designed for the Tempstar TNE100J20G1 and shared across ICP / Heil / Comfortmaker furnaces using a 115V-to-24V 40VA control transformer. Verify your primary line voltage is 115V and the VA rating matches before installing.
Installation Guide
- Safety First — Disconnect power at the furnace switch and breaker and verify zero voltage with a multimeter on both line and load sides.
- Access — Remove the control/electrical compartment service panel.
- Document — Photograph all primary and secondary leads and terminal connections before disconnecting.
- Remove — Label and disconnect the primary (115V) and secondary (24V) wires, then remove the transformer mounting screws.
- Install — Mount the new transformer, reconnect the line side to 115V and the load side to 24V exactly per your photo, and secure all terminals.
- Test — Restore power and confirm 24V at the secondary, a live thermostat, and normal blower/ignition operation.
Signs You Need a Replacement
- No 24V control power — dead thermostat and no furnace response
- Loud humming or buzzing from the transformer
- Burnt smell, scorched casing, or melted insulation
- Open or shorted windings measured with a multimeter
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