Start by removing the grills and burner covers from your existing cooktop.

Next, remove the cabinet doors and pull out the drawers to give yourself enough light and work room.

Turn the handle of the gas shutoff valve so that it is perpendicular to the incoming supply line. This is the "off" position.

Unplug the electrical supply that powers the electronic igniters, and turn off the power at the circuit box.

Loosen and remove the flexible gas supply line from the shutoff valve.

Unfasten any brackets and screws that may be securing the cooktop to the counter.

Once all these screws are removed, the old range should lift out easily.

This new cooktop from Thermador features a star-shaped burner which provides even heating to large pots.

Turn the new range upside down and brush a liberal coating of pipe sealant onto the pipe nipple.

Next, screw on the regulator. This critical fixture keeps incoming gas at the gas pressure at a level that is optimal for the burners. Use an adjustable wrench for the final tightening.

Screw the flexible gas line onto the regulator, and snug it up, using a pipe wrench.

The cooktop is now ready to drop into the countertop opening.

Under the countertop, apply pipe sealant to the end of the gas supply line.

Using two wrenches, tighten the connection between the fexible hose and the gas supply line.