Thermador Gas Cooktop GGS30 Repair

The Thermador GGS30 is a 30-inch, four-burner gas cooktop with a glass cooking surface, four round grates, and four control knobs between the front and rear burners. The two burners on the left use Thermador's ExtraLow system. [0]

Look underneath the cooktop at the right-front corner of the rough-in box for the rating plate. Use the model and serial numbers printed there to identify the unit before ordering parts. [1]

Thermador's parts list shows GGS30 and GGS30W together but assigns different glass-top part numbers to them, so do not identify the model from color alone. The closely related GGSCV30/GGSCV30W models have an integrated Cook'n'Vent opening and extra vent controls; the GGS30 does not. [2][3]

This is a gas appliance. If you smell gas, do not light any appliance, touch an electrical switch, or use a phone in the building. Call the gas supplier from a neighbor's phone and follow its instructions; if the supplier cannot be reached, call the fire department. [4]

Shut off the manual gas valve and unplug the cooktop before opening or servicing it. After reconnecting the gas supply, turn the gas on and check every supply-line connection with a soap solution; bubbles indicate a leak. Never check for gas leaks with a flame. For propane, install conversion kit NLPKIT5 (P/N 35-00-622) and follow its instructions to replace the burner jets and adjust the valves and regulator. [10][6][13]

• Model number: GGS30 [0]
• Appliance type: Built-in glass gas cooktop [7]
• Burners: Four sealed gas burners; the two left burners have ExtraLow settings [0]
• Maximum burner outputs: Front left 9,100 BTU/hr; rear left 11,000 BTU/hr; front right 11,000 BTU/hr; rear right 9,100 BTU/hr [7]
• Ignition: Electronic ignition with automatic reignition [8]
• Overall dimensions: 30 3/4 in wide by 21 3/4 in deep [9]
• Cutout range: 26 1/2-29 7/8 in wide by 18 5/16-20 15/16 in deep [9]
• Cooktop electrical load: 120 V, 60 Hz, 1.0 A [10]
• Required circuit: Grounded 120 V, 60 Hz, 15 A circuit [11]
• Fuel: Factory-configured for natural gas; converts to LP with kit NLPKIT5, P/N 35-00-622 [6]

Document discrepancy: The Care and Use Manual lists minimum outputs of 300 and 365 BTU/hr for the two left ExtraLow burners, while the specification sheet lists 210 and 260 BTU/hr. Both sources agree on the 9,100 and 11,000 BTU/hr maximums. Confirm the unit's rating plate and the applicable document revision if minimum output is important. [0][7]

The rating plate is underneath the cooktop at the right-front corner of the rough-in box. It contains both the model and serial numbers. [1]

Turn every control knob off. On either right-side standard burner, hold a lit match at the burner ports, turn the knob to HI, and wait for the flame to burn all the way around the cap before setting the flame height. The two left ExtraLow burners cannot be used without power. Do not light any burner if you smell gas. [8]

When any burner is turned on, the ignition system sparks all burner igniters. Automatic reignition can also spark when a flame is disturbed or goes out. Persistent or intermittent sparking can be caused by a draft, moisture or cleaner around an igniter, or reversed outlet polarity. [8][1]

Heat can cause the porcelain enamel on burner caps to discolor or develop fine crazing over time. The care manual says this is normal and does not affect burner operation. [12]

Yes. Confirm GGS30 on the rating plate, then install conversion kit NLPKIT5 (P/N 35-00-622). The kit provides replacement burner jets and instructions for adjusting the valves and regulator. After reconnecting the gas supply, check every connection with a soap solution; never use a flame for leak testing. [6][13]

Turn the knob off. After any unburned gas has dissipated, check that the burner cap is seated correctly, the igniter is clean and dry, the burner ports are clear, and the manual gas shutoff valve is open. If the igniter does not spark, check the power cord, circuit breaker, or fuse. [1]

Check for a strong draft and dry any moisture or liquid cleaner around the igniter. Check that the receptacle is correctly polarized. If it is not, disconnect power at the circuit breaker and correct the hot and neutral wiring, or replace it with a correctly grounded and polarized three-prong receptacle. [1][11]

Seat the burner cap correctly, then clear each clogged port with a straightened paper clip, needle, or fine wire—never a wooden toothpick. If the flame remains yellow or incomplete, confirm that the supplied gas matches the cooktop's configuration and check the regulator and supply pressures against the installation table: 5 in. WC manifold pressure for natural gas or 10 in. WC for propane. [8][6][13]

Allow the cooktop to cool before cleaning. Wash removable grates and burner caps with warm, sudsy water and dry them thoroughly before reassembly. Avoid getting excess water or cleaner on the igniters. [12]

If a burner port is clogged, clear it with a straightened paper clip, needle, or similar fine wire. Do not use a wooden toothpick, which can break off in the port. Reinstall each burner cap with its alignment tab in the matching notch, and place each grate with its indexing finger opposite the igniter. [12]

Use a cleaner intended for glass cooktops on the glass surface. Avoid abrasive or caustic cleaners that can scratch the glass or damage markings and finishes. [14]

The attached parts list covers the GGS30/GGS30W family and includes separate diagrams for the maintop, glass, burner box, valves, burner tubing, burner assemblies, spark module, rough-in box, and wiring. Confirm the full model number on the rating plate before ordering a part. [15][3][16]

• Thermador GGS30 Installation Instructions
• Thermador Gas Cooktops Care and Use Manual
• Thermador Gas Cooktops Specification Sheet
• Thermador Glass Gas Cooktops Parts List

• [0] Care and Use Manual, manual p. 7 / PDF p. 9
• [1] Care and Use Manual, manual p. 28 / PDF p. 30
• [2] Parts List, PDF p. 1
• [3] Parts List, diagram p. 3 / PDF p. 6
• [4] Care and Use Manual, manual p. 1 / PDF p. 3
• [5] Installation Instructions, PDF p. 1
• [6] Installation Instructions, PDF p. 2
• [7] Specification Sheet, p. 66 / PDF p. 1
• [8] Care and Use Manual, manual p. 13 / PDF p. 15
• [9] Installation Instructions, PDF p. 5
• [10] Care and Use Manual, manual p. 3 / PDF p. 5
• [11] Installation Instructions, PDF p. 4
• [12] Care and Use Manual, manual p. 22 / PDF p. 24
• [13] Installation Instructions, PDF p. 7
• [14] Care and Use Manual, manual p. 24 / PDF p. 26
• [15] Parts List, contents / PDF p. 3
• [16] Parts List, burner-box diagram p. 5 / PDF p. 8