Unplug the unit! (a jolt as I brushed two of the exposed ignition switches was a painful reminder)I removed the top of the stove by lifting out the burner cartridges and removing all screws on the interior lip of each pan and the fan switch (16 total screws. I slipped of the ignition switches (red rectangles), unscrewed the supply line, and unscrewed the manifold from the shield beneath. I removed the 8 screws holding the shield in place from below. This allowed me to remove the manifold and access the shrew holding the valve from below. I added Teflon tape and replaced the old valve with the new one. DO NOT over tighten this screw. I then replaced the supply lines and tested the system with leak detector spray. Once everything checked out I reassembled in reverse order. The pans are tricky to replace the frame screws. I used a rubber potholder to gain some grip to lift the pan into the frame. Repair manual says to remove the entire unit for servicing but you only need to access two screws on the side. Vicegrips worked for me to spin them out between the stove and the countertop.