Tempstar 40VA Transformer for T8MPT050B12A1 — 115V to 24V | Ships Today
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Overview
This OEM control transformer (part #1012722) steps the incoming 115V line voltage down to the 24V control voltage that operates your Tempstar T8MPT050B12A1 furnace's thermostat, gas valve, igniter circuit, and control board. Rated at 40VA, it supplies the low-voltage power that the entire control system depends on. When a transformer fails, the furnace goes completely dead on the low-voltage side: the thermostat screen may go blank, the unit won't respond to a call for heat, and you may find a blown low-voltage fuse on the control board. A buzzing, overheating, or visibly scorched transformer is a sure sign of failure and should be replaced promptly to protect downstream components.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1012722 |
| Type | Control Transformer |
| Brand | Tempstar |
| Primary Voltage | 115V |
| Secondary Voltage | 24V |
| Rating | 40VA |
| Fitment | OEM |
Compatibility
Engineered as a direct-fit replacement for the Tempstar T8MPT050B12A1 gas furnace. This transformer is also commonly shared across the ICP family of furnaces (Tempstar, Heil, Comfortmaker, and Arcoaire) that use the same 115V-to-24V 40VA control circuit. Verify your existing transformer's VA and voltage ratings 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 access panel.
- Document — Photograph all primary (line) and secondary (24V) wire connections before disconnecting.
- Remove — Disconnect the wire leads, remove the mounting screws, and lift out the old transformer.
- Install — Mount the new transformer, reconnect the 115V primary and 24V secondary leads exactly per your photo.
- Test — Restore power, confirm 24V at the secondary, and verify the furnace responds to a call for heat.
Signs You Need a Replacement
- Furnace is completely unresponsive to the thermostat
- Blown low-voltage fuse on the control board (often repeatedly)
- No measurable 24V output at the secondary terminals
- Transformer is hot to the touch, 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