Tempstar Transformer for T8MPN100F14A1 — 40VA 115V to 24V | Ships Today
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Overview
This is a genuine OEM 40VA control transformer (part number 1012722) for the Tempstar T8MPN100F14A1 gas furnace. The transformer steps line voltage of 115V down to the 24V low-voltage control circuit that powers the thermostat, gas valve, ignition control, and relays. Rated at 40VA, it delivers the steady, regulated 24V supply your control board and safety circuits require. When a transformer fails, the furnace typically goes completely dead on the control side — no thermostat response, no ignition sequence, and often a blown low-voltage fuse caused by a shorted secondary winding.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1012722 |
| Type | Step-Down Control Transformer |
| Brand | Tempstar (ICP/Heil/Comfortmaker) |
| Rating | 40VA |
| Primary Voltage | 115V |
| Secondary Voltage | 24V |
| Fit | OEM Direct Replacement |
Compatibility
Engineered as the factory-correct replacement for the Tempstar T8MPN100F14A1 furnace. Because ICP builds the Tempstar, Heil, and Comfortmaker lines on shared platforms, this 40VA transformer also services many sibling T8MPN-series furnaces using the same control architecture. Confirm your existing transformer is rated 115V-to-24V at 40VA before installing.
Installation Guide
- Safety First — Disconnect power at the furnace switch and breaker, then verify zero voltage with a multimeter.
- Access — Remove the furnace control/blower compartment panel.
- Document — Photograph the primary and secondary lead connections before disconnecting.
- Remove — Disconnect the primary (line) and secondary (24V) leads, then unbolt the transformer from its mounting bracket.
- Install — Mount the new transformer, reconnect primary to line voltage and secondary to the 24V control terminals exactly as photographed.
- Test — Restore power, confirm 24V at the secondary with a meter, and run a full heat cycle.
Signs You Need a Replacement
- Furnace control board and thermostat are completely dead with line voltage present
- Repeatedly blown 3A or 5A low-voltage control fuse
- No 24V reading across the secondary terminals
- Burnt smell or visibly scorched transformer windings
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