Tempstar 40VA Transformer for T9MPV050F12A3 — 115V to 24V | Ships Today
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Overview
This is a genuine OEM control transformer (part number 1012722) for the Tempstar T9MPV050F12A3 variable-speed gas furnace. It steps the 115V line voltage down to the 24V secondary that powers the furnace control board, gas valve, thermostat circuit, and relays. Rated at 40VA, it supplies enough capacity to drive the low-voltage controls plus a typical accessory load. When a transformer fails, the entire 24V control system goes dead: no thermostat display, no blower or ignition response, and no heating or cooling. Failures are usually caused by a shorted secondary, an overloaded circuit, or a power surge, and an open thermal fuse inside the windings is a common end-of-life symptom.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1012722 |
| Description | Transformer (TRANS 115>24 40VA) |
| Type | Control / Step-Down |
| Brand | Tempstar (ICP / Heil) |
| Primary Voltage | 115V |
| Secondary Voltage | 24V |
| Rating | 40VA |
| Fit | OEM Replacement |
Compatibility
Direct OEM replacement for the Tempstar T9MPV050F12A3 variable-speed gas furnace and shared across ICP-family equipment (Tempstar, Heil, Comfortmaker, and related Carrier/ICP platforms). Confirm the 115V primary / 24V secondary, 40VA rating, and part number 1012722 against your existing transformer before installing.
Installation Guide
- Safety First — Disconnect power at the furnace switch and breaker; verify zero voltage with a multimeter before handling wiring.
- Access — Remove the control compartment service panel.
- Document — Photograph every primary and secondary lead and terminal before disconnecting.
- Remove — Disconnect the line-voltage primary leads and the 24V secondary leads, then unbolt the transformer from its mounting bracket.
- Install — Mount the new transformer, reconnect the 115V primary and 24V secondary leads exactly per your photos, and secure all connections.
- Test — Restore power and confirm 24V at the secondary with a multimeter, then verify the thermostat, blower, and ignition respond normally.
Signs You Need a Replacement
- Dead thermostat display and no 24V control power
- Furnace completely unresponsive to heating or cooling calls
- No measurable 24V at the secondary terminals under load
- Repeated blown control fuses or a burnt-smelling transformer
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