Tempstar PTAC Thermostat for THA12K25STD — OEM Part 1058517 | Ships Today
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Overview
This is the genuine OEM PTAC thermostat (OEM part number 1058517, "TSTAT PTAC X") for the Tempstar THA12K25STD heat pump system. The thermostat is the brain of your packaged terminal air conditioner and heat pump, reading room temperature and sending the call for cooling, heating, and fan operation to the unit's control logic. When this control fails, the system loses its ability to maintain setpoint accurately — leading to short cycling, no response to setpoint changes, or a unit that runs continuously. Installing the exact OEM thermostat guarantees correct terminal mapping and reliable operation that aftermarket universal controls often cannot match.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1058517 |
| Description | TSTAT PTAC X |
| Type | PTAC Thermostat Control |
| Brand | Tempstar (ICP / Heil) |
| Application | Heat Pump / Air Handler |
| Fits Model | THA12K25STD |
| Fitment | OEM Replacement |
Compatibility
This thermostat is the factory-specified control for the Tempstar THA12K25STD. Because ICP builds Tempstar, Heil, and Comfortmaker units on shared platforms, OEM part 1058517 also serves equivalent THA12-series PTAC heat pump models. Always confirm your model and serial against the unit data plate before ordering.
Installation Guide
- Safety First — Disconnect power at the breaker or unit disconnect and verify zero voltage with a multimeter before touching any wiring.
- Access — Remove the front grille and service panel to reach the control compartment.
- Document — Photograph every wire and terminal connection on the existing thermostat before disconnecting anything.
- Remove — Label and disconnect the low-voltage leads, then unclip or unscrew the failed thermostat from its mount.
- Install — Mount the new 1058517 thermostat and reconnect each lead exactly per your reference photo.
- Test — Restore power and verify the unit responds correctly to cool, heat, and fan calls.
Signs You Need a Replacement
- Unit does not respond to setpoint changes or stays at one temperature.
- System short cycles or runs continuously regardless of room temperature.
- Blank, frozen, or erratic display and controls.
- No cooling or heating call sent to the unit despite a working compressor and fan.
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