Tempstar 40VA Transformer for T8MPN150J20A1 — 115V to 24V Control | Ships Today
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Overview
This genuine OEM 40VA control transformer (part #1012722) powers the 24-volt control circuit on the Tempstar T8MPN150J20A1 gas furnace. It steps line voltage of 115V down to 24V to drive the control board, gas valve, thermostat, and relays. A failed transformer is one of the most common reasons a furnace goes completely dead: no thermostat display, no control-board lights, and no call for heat. Transformers fail from age, a shorted low-voltage circuit, or a stuck contactor that overdraws the secondary winding. This 40VA unit delivers ample capacity for the furnace's 24V loads with margin for a wired-in accessory such as a humidifier or condensate switch.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1012722 |
| Description | Transformer 115V to 24V, 40VA |
| Type | Step-down control transformer |
| Brand | Tempstar |
| Primary Voltage | 115V |
| Secondary Voltage | 24V |
| Rating | 40VA |
| Fitment | OEM replacement |
Compatibility
Built for the Tempstar T8MPN150J20A1 furnace and compatible with many ICP-manufactured Tempstar, Heil, Comfortmaker, and Carrier/Bryant furnaces that use a 115V-to-24V 40VA control transformer. Confirm the primary tap voltage and mounting bracket match your existing unit.
Installation Guide
- Safety First — Disconnect power at the switch and breaker and verify zero voltage with a multimeter on both the line and 24V circuits.
- Access — Remove the furnace control-compartment service panel.
- Document — Photograph every primary and secondary lead before disconnecting.
- Remove — Label and disconnect the wires, then unbolt the old transformer from its bracket.
- Install — Mount the new transformer, reconnect the 115V primary and 24V secondary leads exactly as photographed.
- Test — Restore power, confirm 24V at the secondary with a meter, and verify the furnace responds to a call for heat.
Signs You Need a Replacement
- Furnace is completely dead with a blank thermostat
- No 24V output measured at the transformer secondary
- Visible scorching, swelling, or a burnt smell from the transformer
- Repeated blown low-voltage fuse after the short is cleared
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