Thermador Star Burner Won't Ignite

The short answer: a Thermador Star burner that clicks without lighting has a working igniter and a gas-delivery or spark problem. Start by drying the burner cap and base, reseating the cap flush over its star-shaped ports, and clearing any spillover crust around the igniter. Those three checks resolve most cases. If the burner still will not catch, the igniter electrode or the spark module has weakened and the fix moves into a service call.

How the Star Burner Lights

Thermador's Star burner spreads flame across five points rather than a plain ring, which is why it heats evenly and simmers well. To light it, a spark electrode sits at the edge of the burner and arcs to the metal cap. That spark ignites gas flowing up through the star-shaped ports. Three things have to be right for that to work: the cap has to sit flush so the ports line up and the electrode gap is correct, the electrode has to be clean and dry so the spark is strong, and gas has to reach the ports without obstruction. When a burner clicks but stays dark, one of those three is off.

The Usual Causes, Ranked

A Wet or Misaligned Cap

This is the number one reason a Thermador burner clicks and does nothing, especially right after cleaning. If the cap is even slightly damp, the spark grounds through the water instead of jumping a clean arc, and the ports never light. A cap set back down crooked has the same effect, because the electrode gap is thrown off and the ports do not line up with the gas holes. Lift the cap, dry it and the burner base completely with a towel, then set the cap back down so it sits flat and level with no rock to it. Run a straightened paperclip around the star ports to clear any dried food or cleaning residue while the cap is off.

A Fouled or Cracked Igniter

The igniter electrode is a small ceramic-tipped post at the burner's edge. Boilovers coat it in carbon, and over the years the ceramic can hairline-crack. A fouled tip weakens the spark; a cracked one lets the spark leak to ground so it never reaches the cap. Wipe the tip clean with a dry toothbrush and look closely for cracks in the white ceramic. A cracked electrode is not a cleaning fix, it is a replacement, and it is a common one on Pro Grand and Pro Harmony cooktops that see heavy use.

What a Technician Checks

When the owner steps do not clear it, the diagnosis gets specific. The technician measures the spark at the electrode to confirm whether the module is delivering full voltage, checks the electrode gap and the ceramic for cracks, and tests the switch behind each knob, since a shorted switch is what makes every burner click at once. Gas pressure at the manifold is verified when a burner lights but will not hold a low flame. Thermador spark modules and igniters are model-specific between the Pro Grand, Pro Harmony, and Masterpiece cooktops, so matching the right Genuine OEM Parts on the diagnostic visit matters.

When to Book a Repair

Try the dry-and-reseat and the igniter clean first, they resolve a large share of these no-ignition cases. Book service when a single electrode is cracked, when all burners click even after the cooktop is dry, when there is no click at all, or when a burner lights but drops out on the low setting. Gas cooktop work involves live fuel lines and electrical parts that need proper testing. Completed repairs include a 180-day repair warranty. Written terms are provided with the repair.

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