Tempstar 40VA Transformer for T8MPV050B12B1 — 115V to 24V | Ships Today
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Overview
This OEM control transformer (part #1172810) steps down 115-volt line power to the 24-volt control voltage your Tempstar T8MPV050B12B1 furnace needs to operate. Rated at 40VA, it powers the thermostat, gas valve, control board, and relays throughout the system. When a transformer fails, the entire low-voltage control circuit goes dead — the thermostat screen goes blank, the furnace will not respond to a heat or cool call, and you may smell burnt insulation or find a blown low-voltage fuse on the control board. A buzzing transformer or one that trips its internal thermal protection repeatedly is also on its way out. This is a genuine OEM Class 2 transformer built to the exact electrical and mounting specifications of your unit.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1172810 |
| Type | Control Transformer |
| Brand | Tempstar (ICP / Heil) |
| Primary Voltage | 115V |
| Secondary Voltage | 24V |
| Rating | 40VA |
| Class | Class 2 |
| Fits Model | T8MPV050B12B1 |
Compatibility
Engineered for the Tempstar T8MPV050B12B1 gas furnace and shared across many ICP-family platforms including Heil, Comfortmaker, and Arcoaire furnaces that use a 115V-to-24V 40VA control transformer. Always confirm your old transformer is rated 115V primary / 24V secondary / 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 service panel.
- Document — Photograph all primary (line) and secondary (24V) wire connections before disconnecting.
- Remove — Disconnect the four leads, remove the mounting screws, and lift out the failed transformer.
- Install — Mount the new transformer, reconnect primary and secondary leads exactly as photographed.
- Test — Restore power, confirm 24VAC across the secondary terminals, and verify the furnace responds to a thermostat call.
Signs You Need a Replacement
- Blank thermostat and no furnace response on a heat or cool call
- Repeatedly blown 3-amp low-voltage fuse on the control board
- Audible buzzing or a burnt-electrical smell at the transformer
- No measurable 24VAC at the secondary terminals
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