Tempstar PTAC Thermostat for THA12K50STA – OEM Part 1058517 | Ships Today

Overview

This is the genuine OEM PTAC thermostat (factory part number 1058517, "TSTAT PTAC X") for the Tempstar THA12K50STA packaged terminal air conditioner / heat pump. The thermostat is the control interface that reads room temperature and signals the unit to cycle heating and cooling to maintain the setpoint. When this component fails, the unit may stop responding to temperature changes, short-cycle, run continuously, or fail to switch between heat and cool modes. Replacing a worn or unresponsive thermostat with the correct OEM part restores reliable, accurate temperature control without guesswork over compatibility.

Specifications

Compatibility

Engineered as a direct-fit replacement for the Tempstar THA12K50STA PTAC system. Because this is the same factory part (1058517) used across the ICP/Heil/Tempstar PTAC platform, it also services closely related THA12-series units. Confirm the part number on your existing thermostat or unit data plate before ordering to guarantee an exact fit.

Installation Guide

1. Safety First – Disconnect power to the PTAC unit at the breaker and verify zero voltage with a multimeter before touching any wiring.
2. Access – Remove the front grille and service panel to expose the control compartment.
3. Document – Photograph all thermostat wire connections and terminal positions before disconnecting anything.
4. Remove – Label and disconnect the wiring from the old thermostat, then release its mounting clips/screws and lift it out.
5. Install – Mount the new thermostat in the same position and reconnect each wire exactly per your reference photo.
6. Test – Restore power, set a cooling and a heating call, and confirm the unit responds correctly to the new setpoints.

Signs You Need a Replacement

• Unit no longer responds to temperature setting changes.
• Room temperature drifts far from the setpoint or the unit short-cycles.
• Heating or cooling mode will not engage or won't switch over.
• Blank, frozen, or erratic thermostat display/controls.

Shipping & Returns

Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.