Step1: Disconnect electrical power and shut off the gas supply to the equipment.
Step2: Allow the unit to cool completely before servicing.
Step3: Remove the control panel and disconnect the existing thermostat wiring.
Step4: Carefully remove the sensing bulb and capillary tube from their mounting locations.
Step5: Install the new thermostat, routing the capillary tube without sharp bends.
Step6: Secure the sensing bulb in its original position and reconnect the wiring.
Step7: Reassemble the panel, restore power and gas, then verify temperature operation and calibration.