The Thermador HGSI42TS is a gas cooktop with sealed burners and continuous grates. It does not have a glass top, so there is no glass component to replace. The cooktop typically consists of a stainless steel or ceramic surface, depending on the specific model. If you are experiencing any issues with your Thermador HGSI42TS cooktop, it is essential to follow the manufacturer's recommendations for maintenance and repair. For any repairs or replacements involving gas appliances or cooktop components, it is crucial to prioritize safety and consult a qualified technician or contact Thermador's customer support for assistance. Attempting to replace any parts or perform repairs without the proper knowledge and experience can be hazardous and may lead to damage to the cooktop or pose safety risks. It could also void any existing warranty. If your Thermador HGSI42TS cooktop requires service or maintenance, it is best to contact Thermador's customer support or an authorized service center. They can provide you with the appropriate guidance, schedule a service appointment, and ensure that the necessary repairs or replacements are carried out safely and effectively. Always refer to the product manual and warranty documentation for specific instructions and warranty coverage details. For the most accurate and up-to-date information, contact the manufacturer or an authorized service center.