Shut off the gas supply at the stopcock installed in the gas line closed to the water heater. The handle of the stopcock should be perpendicular to the gas supply pipe. Also shut off the water supply .
Drain the water from the old heater by hooking garden hose up to the sillcock drain and running it to a floor drain. If you don’t have a floor drain , drain the water into buckets . For your personal safety , wait until the water heater has been shut off for a couple of hours before draining it.
Disconnect the gas supply from the water heater . To do so, loosen the flare fitting with two wrenches or pliers in a soft copper supply line or loosen the union fitting with two pipe wrenches of black pipe supply lines .
Disconnect the vent pipe from the draft hood by withdrawing the sheet metal screws connecting the parts . Also remove vent pipes up to and including the elbow so you may inspect them for corrosion buildup and replace if needed .
Cut the water supply lines. Prior shut off the cold water supply either at the stop valve near the heater or at valve in new condition , replace it with a ball valve .
Remove the old heater and dispose of it properly . Most trash collection companies will haul it away 20 dollars or 30 dollars . Don’t simply leave it out at the curb unless you know that is allowed by you municipal water collection department . A two wheel truck or appliance dolly is a big help here. Water heaters usually weigh around 150 pounds .
Position the new until installation area. If you have flooring you wish to protect formless, settle unit on a drip pan ( available where water heater accessories are sold ).The shallow pans feature a hose bib so you can run a drain line from the pan to floor drain . If the water heater is not level, level by shimming under the bottom with a metal or composite shim. Note you ‘ll need to shift the unit around a bit to have clearance for installing the water supply connectors.
Install a Relief valve and its important to change your supply lines every 5 years. Prepare the new water heater for installation . Before you put you put the water heater in place , add a T & P ( temperature and pressure) relief valve at the valve opening . Make sure to read the manufacturer’s instructions and purchase the recommended valve type. Lubricate the threads and tightened the valve into the valve into the valve opening with a pipe wrench. Note The water heater shown in this sequence came with a T & relief valve that’s preinstalled .
Things may be easy to fix gas heaters have pilot and trip it and relight is , on the bottom in plated gas you will see it through there and little flame will show though the plated glass.