Thermador Oven Not Heating? How to Fix It

When your Thermador oven stops heating, it can throw your entire cooking routine off track. Thermador ovens are reliable, but like any oven, they can develop issues over time. 

Heating issues might seem intimidating, but the solutions are generally straightforward and don’t require complex repairs.

Before troubleshooting, it helps to know how your oven works.

• Electric models use heating elements: one at the bottom for baking and another at the top for broiling.
• Gas models use an igniter and burner assembly to generate and regulate heat.

Knowing which type you have makes it easier to pinpoint where the issue lies.

Let’s look at the most common causes and what you can do to fix them.

Common Causes of Heating Problems

1. Power Supply Issues

If your electric Thermador oven isn’t heating at all, start by checking the power source.
Make sure the plug is secure and the circuit breaker hasn’t tripped. Electric Thermador ovens require a dedicated 240-volt circuit, and even a partial power loss can prevent the elements from working properly.

If the breaker keeps tripping, there may be a deeper electrical issue that needs professional attention.

2. Faulty Heating Elements

For electric ovens, a burned-out heating element is one of the most common reasons for heat loss.

The bake element, located at the bottom, provides most of the heat during cooking. Look for visible damage such as cracks, blisters, or dark spots. When functioning correctly, it should glow bright red once the oven preheats.

If it stays dark or heats unevenly, the element likely needs replacement. The same applies to the broil element at the top, though it tends to last longer since it’s used less often.

3. Defective Temperature Sensor

The temperature sensor (or oven sensor probe) monitors the oven’s internal temperature and communicates with the control board. If the sensor fails, your oven may not heat correctly or may shut off too soon.

It’s usually located at the upper back of the oven cavity. A technician can test it with a multimeter. It should measure around 1,100 ohms at room temperature. If the reading is far off, the sensor is faulty and should be replaced.

4. Broken Igniter (Gas Models)

If you have a gas Thermador oven that won’t heat, the igniter is often the culprit.

The igniter’s job is to both spark the flame and act as a safety device. Over time, it can weaken and fail to open the gas valve.

Signs of a bad igniter include:

• Clicking sounds with no flame
• A glowing igniter that never lights the burner
• Long delays before ignition

Replacing an igniter usually solves the problem, but because gas repairs involve safety risks, this is best left to a qualified appliance repair technician.

5. Malfunctioning Control Board

The electronic control board manages the oven’s heating cycles. If it fails, you might notice:

• No response when you set a temperature
• Incorrect temperature readings
• Error codes on the display

Sometimes the issue is as simple as a loose wire connection, but other times, the board itself may need replacement. This part is expensive, so it’s worth confirming all other components are working before replacing it.

How to Troubleshoot Your Thermador Oven

1. Safety First

Always start by cutting power to the oven.

Turn off the circuit breaker for electric models or close the gas supply valve for gas models. Allow the oven to cool completely before inspecting anything.

2. Visual Inspection

Open the oven and take a close look inside. 

Check for:

• Burn marks or damaged wiring
• Cracked or blistered heating elements
• Loose connections or corrosion

Sometimes, a quick visual check reveals the problem immediately.

3. Test the Heating Elements

After ensuring it’s safe, turn the power back on and set the oven to bake at 350°F. The bake element should glow red within a few minutes. If it doesn’t, it has likely failed.

For confirmation, turn the power back off and use a multimeter to test for continuity. A working element should show continuity; if not, it should be replaced.

4. Check the Temperature Sensor

Disconnect the sensor and measure its resistance with a multimeter. At room temperature, it should read close to 1,100 ohms. If the reading is much higher or lower, or if there’s no continuity, the sensor isn’t communicating correctly with the control board.

5. Examine the Control Board

If everything else checks out, inspect the control board for signs of damage such as burnt areas, loose wires, or swollen components. Some problems are visible, but diagnosing electronic faults usually requires professional tools and experience.

Frequently Asked Questions

Can I fix a Thermador oven that won’t heat myself?

Yes, for basic issues. You can safely check the power supply, inspect heating elements for visible damage, and clean the oven interior. However, gas component repairs, control board replacements, and internal wiring work should be handled by a certified technician. Gas work carries safety risks, and electrical diagnostics require specialized tools and knowledge.

How long do Thermador oven heating elements last?

Heating elements typically last 8 to 15 years with normal use. The bake element sees more wear than the broil element since it’s used more frequently. Heavy use, frequent self-cleaning cycles, and food spills can shorten their lifespan.

Will my warranty cover heating problems?

It depends on your warranty terms and what caused the problem. Check your documentation, and remember that DIY repairs on certain components can void coverage. When in doubt, contact a certified service provider first.

Why does my oven take forever to preheat?

Slow preheating usually means a heating element is weakening but hasn’t completely failed yet. It might also indicate a faulty temperature sensor that’s misreading the oven temperature. If preheating takes significantly longer than usual, have the elements and sensor tested.

How often should I have my Thermador oven serviced?

For gas models, an annual inspection is recommended to check the igniter, burner, and gas connections. Electric models typically need less frequent servicing unless you notice performance issues. Regular cleaning and attention to how your oven performs will help you catch problems early.