File:Natural gas regulator.jpg

Summary
Photo of a typical pressure regulator on a late-model (ca. 2007) North American water heater. Visible are:
 * 1) the temperature-setting (thermostat) dial on the front (marked Hot/Warm/Vaction)
 * 2) the main off/pilot/on valve, on top (currently "on")
 * 3) the pilot light override pushbotton, immediately to the left of the off/pilot/on valve
 * 4) the button for the piezoelectric igniter, mounted on the right side of the regulator

The black pipe entering at the left is the gas supply. The four tubes/wires leading down are (from left to right): the pilot light sensor (thermocouple); the main burner gas line; the pilot light gas line; and the piezoelectric igniter wire.

See also Image:Gas supply line trap.JPG.