How to Install a Gas Water Heater - The Home Depot
If you are not familiar with connecting black iron pipes there are gas water heater installation kits available. If using a kit follow the manufacturers guidelines. Assemble and tighten each fitting with two pipe wrenches. Install the union fitting last since it connects the new line to the existing line. Apply gas-rated pipe joint compound to the unions flare connection. Turn on the water supply.
Flue Gas Spill Switch Installation Spill switch hookup ...
The actual connection of the flue gas spill switch wires can vary but a typical connection wires the switch in series with one of the thermostat wires that connect between the thermostat and terminals on the gas valve that in turn turns opens to provide fuel gas to the gas burner.