Tempstar PTAC Thermostat for THA09R25STB — OEM Part 1058517 | Ships Today

Overview

This is the genuine OEM thermostat (part number 1058517, "TSTAT PTAC X") for the Tempstar THA09R25STB packaged terminal air conditioner/heat pump. The PTAC thermostat is the user-facing control that reads room temperature and signals the unit to cycle heating, cooling, and fan operation. When this control fails, the unit may stop responding to temperature changes, run continuously, fail to switch between heat and cool, or go completely unresponsive. Replacing a worn or faulty thermostat restores accurate temperature control and proper cycling to your PTAC system.

Specifications

Compatibility

This thermostat is the factory-specified control for the Tempstar/Heil/ICP THA09R25STB PTAC unit. It is also shared across closely related THA09 series PTAC models. Always verify the part number on your existing control matches 1058517 before ordering to ensure correct fitment.

Installation Guide

1. Safety First — Disconnect power to the PTAC unit at the breaker or unplug it, and verify zero voltage with a multimeter before touching any wiring.
2. Access — Remove the front cover/service panel to expose the control and wiring.
3. Document — Photograph all wire connections and terminal positions before disconnecting anything.
4. Remove — Disconnect the thermostat wiring harness and release the old thermostat control from its mounting.
5. Install — Mount the new thermostat and reconnect the wiring exactly per your reference photo.
6. Test — Restore power, set a call for heating and cooling, and verify the unit responds and cycles correctly.

Signs You Need a Replacement

• Unit does not respond to temperature setpoint changes
• System runs continuously or short-cycles regardless of room temperature
• Display is blank, frozen, or unresponsive
• Unit will not switch between heating and cooling modes

Shipping & Returns

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