Tempstar 40VA Transformer for T9MPX080J16A2 — 115V to 24V Step-Down | Ships Today
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Overview
This OEM control transformer (part number 1172810) steps 115V line voltage down to the 24V low-voltage power your Tempstar T9MPX080J16A2 furnace needs to operate its control board, thermostat circuit, gas valve, and ignition system. Rated at 40VA, it delivers steady, regulated power to every 24V component. When the transformer fails, the whole control circuit loses power: the thermostat goes dark, the furnace ignores calls for heat, and the board shows no low-voltage supply. Buzzing, a burnt smell in the control compartment, or repeatedly blown low-voltage fuses point to a failed or overloaded transformer. A genuine OEM 40VA replacement restores correct voltage and protects the rest of the control circuit.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1172810 |
| Type | Step-Down Control Transformer |
| Brand | Tempstar (ICP / Heil) |
| Primary Voltage | 115V |
| Secondary Voltage | 24V |
| Rating | 40VA |
| Fit | OEM Direct Replacement |
Compatibility
Engineered as a direct OEM fit for the Tempstar T9MPX080J16A2 gas furnace. The 1172810 transformer is shared across many ICP-family furnaces sold under the Tempstar, Heil, and Comfortmaker brands. Verify your existing transformer is a 115V-to-24V 40VA unit 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 service panel.
- Document — Photograph all primary and secondary wire connections before disconnecting.
- Remove — Disconnect the 115V primary and 24V secondary leads, then unbolt the failed transformer from its mounting bracket.
- Install — Mount the new transformer and reconnect primary and secondary leads exactly per your photo.
- Test — Restore power and confirm 24V across the secondary and a normal call for heat.
Signs You Need a Replacement
- Blank thermostat and no 24V power at the control board.
- Furnace does not respond to a call for heat.
- Audible buzzing or burnt smell from the control compartment.
- Repeated blown low-voltage fuses or no secondary output on 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