Tempstar 40VA Transformer for T8MPN050B12A1 — 115V to 24V Control Transformer | Ships Today
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Overview
This genuine OEM control transformer (part number 1012722, TRANS 115>24 40VA) steps the 115V line voltage down to the 24V control voltage that powers the thermostat, gas valve, relays, and control board on the Tempstar T8MPN050B12A1 furnace. Rated at 40VA, it provides ample capacity for the furnace's low-voltage control circuit. When a transformer fails — often from a shorted thermostat wire or a stuck contactor drawing excess current — the entire 24V system goes dead: no thermostat display, no blower, no ignition. A failed transformer frequently takes out an inline fuse on the control board, so inspect and replace that fuse as well. Installing the correct 40VA OEM transformer restores reliable control power.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1012722 |
| Type | Step-Down Control Transformer |
| Brand | Tempstar (ICP / Heil) |
| Rating | 40 VA |
| Primary Voltage | 115V |
| Secondary Voltage | 24V |
| Fits Model | T8MPN050B12A1 |
| Fitment | Genuine OEM |
Compatibility
Factory control transformer for the Tempstar T8MPN050B12A1 gas furnace. As a common ICP-built component, part 1012722 services a wide range of ICP, Heil, and Comfortmaker furnaces and air handlers using a 115V-to-24V 40VA control circuit. Confirm voltage and VA against your unit before ordering.
Installation Guide
- Safety First — Disconnect power at the switch and breaker and verify zero voltage with a multimeter.
- Access — Remove the furnace control/service panel.
- Document — Photograph all primary (line) and secondary (24V) wire connections before disconnecting.
- Remove — Disconnect the leads, remove the mounting screws or nut, and lift out the failed transformer.
- Install — Mount the new 40VA transformer, reconnect the 115V primary and 24V secondary leads exactly per your photo, and check the control-board fuse.
- Test — Restore power, confirm 24V at the secondary with a meter, and verify the thermostat, blower, and ignition respond normally.
Signs You Need a Replacement
- No 24V control power — dead thermostat and no system response
- Repeatedly blown 3-amp control-board fuse
- Burnt smell or visibly scorched/melted transformer housing
- Measured secondary voltage well below 24V under load
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