Safety First, No Flames

Remember that you're going to be working with something that explodes. You could easily turn your house into a neighborhood nightmare. DO NOT EXPOSE NATURAL GAS TO AN OPEN FLAME, your house could blow up at worst, or you could be bald at best (sorry if you're already bald).

Teflon Tape

Wrap all connections with a coat of Teflon tape (or similar product) and twist them down snug. In this install, I used existing plumbing. In areas where flexible gas lines are within code, I suggest them. Otherwise, you have to have special couplers and follow an installation order, like you see here. Install pipe into the thermostat and then assemble the fittings in the reverse order that you removed them in. Lastly connect the compression fitting and reopen the gas valve. Smell the area and listen for leaks. If you smell gas, make sure the thermostat is set to off and give it a minute. Natural Gas disperses fairly quickly, so if you still smell gas after a minute, shut the valve off. Leave the heater alone for 10 minutes and then come back to it. See if you smell gas. If no, open the valve again and see if you smell gas again. If you do, check your pipes and fittings. You should have enough tape on your threads that you can still see it once installed, and disconnec the compression (with the valve off) and see if you can tighten anything any more. Once there is no gas leak, let's light the pilot.

Lighting The Pilot

Many natural gas water heaters today have very nice ignition systems. The one I installed here, for example has a button that you push to light the pilot. No matches, no removing any shields. It's very simple, turn the thermostat down, set the dial on Pilot and press the button down. Click the Pilot Light button. An electronic spark will attempt to light the pilot for you. You watch through a little peep hole to see when the pilot is lite. On a new install, you have to bleed air out of the gas line, so you may have to click for awhile, but it'll eventually kick in.

If the water heater you bought has to be manually lit, you'll have to dig out those matches that you hid and follow these same procedures while trying to fumble with getting the match to the pilot line before it burns out (or burns your fingers). I think they're gonna stop making those kinds if they haven't already.

Once the pilot is lit, you can release the button and stop clicking. Then turn the thermostat to on. Adjust the temperature to your liking, and you should hear it fire up. Great job, you replaced your own Natural Gas Water Heater. Most heaters today will have your tank to temperature in about 45 minutes to an hour. Come back in 30 minutes and make sure that there are still no leaks and that everything looks ok. The burner should still be working until it gets the tank up to temperature.