LG Oven Thermostat Replacement — Gas Oven Temperature Control

The term thermostat in LG oven context refers to different components depending on the oven type. Older LG gas ovens use a capillary tube thermostat — a mechanical device with a liquid-filled sensing tube inside the cavity connected to a valve body that regulates gas flow. Newer electronic LG ovens use the RTD temperature sensor and control board for temperature regulation, with no mechanical thermostat.

Capillary Tube Thermostat (Older Gas Ovens)

The capillary tube thermostat is a mechanical temperature regulator that was common in gas ovens before electronic controls. A liquid-filled copper tube extends from the thermostat valve body into the oven cavity. As the oven heats, the liquid expands and pushes a diaphragm in the valve body that adjusts the gas flow rate.

When this thermostat fails, temperature regulation is lost — the oven runs too hot, too cold, or cycles wildly between extremes. On older LG gas models with knob controls, the thermostat is often integrated with the temperature control knob mechanism.

Electronic Temperature Control (Modern LG Ovens)

Modern LG ovens do not have a traditional thermostat. The RTD temperature sensor (see sensor replacement guide) provides temperature data to the control board, which modulates the heating element or gas valve electronically. If your LG oven has a digital display and electronic controls, you do not have a thermostat — you have a temperature sensor.

Identifying Which System You Have

Part Numbers and Pricing

Capillary Thermostat Replacement

This is a more involved repair than RTD sensor replacement. The thermostat valve body connects to the gas supply line, requiring gas line disconnection. The capillary tube must be carefully routed through the oven without kinking — a kinked tube will not read temperature correctly.

Shut off gas supply. Disconnect power. Pull the oven away from the wall. Access the thermostat valve body from behind the control panel. Disconnect the gas line fittings (two — inlet and outlet). Remove the knob and mounting hardware. Carefully extract the capillary tube from the oven cavity.

Install the new thermostat in reverse order. Route the capillary tube along the same path as the original — avoid sharp bends. Reconnect gas lines and test for leaks with soap solution on all fittings. Restore gas and power. Test temperature accuracy with an oven thermometer.

Gas Safety Considerations

Capillary thermostat replacement involves disconnecting gas lines. Always test for leaks after reassembly using soapy water on every fitting — any bubbles indicate a gas leak that must be corrected before using the oven. If you are not experienced with gas line connections, hire a professional.

Temperature Calibration

After thermostat replacement, verify temperature accuracy at multiple setpoints (300F, 350F, 400F) with an oven thermometer. Capillary thermostats often have a calibration screw on the valve body that allows fine adjustment. Turn the screw in small increments (1/8 turn) and retest.

Frequently Asked Questions

My LG gas oven runs too hot. Is the thermostat bad?

If you have an older model with knob controls and a capillary thermostat, the thermostat may be miscalibrated or failing. Try the calibration screw first. If it has electronic controls, the issue is the RTD sensor or control board.

Can I replace a capillary thermostat with an electronic sensor system?

No — these are fundamentally different systems. The capillary thermostat is a self-contained mechanical regulator. Electronic control requires a different control board, sensor, and wiring harness. Replace like-for-like.

Is gas oven thermostat replacement a DIY job?

It involves gas line disconnection and reconnection. If you are comfortable with gas fittings and leak testing, it is manageable. If not, hire a licensed technician — gas leaks are dangerous.

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