Installing an 80 Gallon Hot Water Heater

Planning

Establish a proper location and correct clearance for the area in which you will install the 80-gallon water heater. Generally, most installations require about a 2-foot clearance between surrounding walls and the water heater and at least 30 inches between the top of the unit and the ceiling and duct work. Dimensions on most 80-gallon units are approximately 24 inches x 24 inches x 63 inches. The unit must be able to fit safely into the desired area.

Arrangement

Typically, 80-gallon water heaters are large. Bringing one into an exposed basement is relatively easy and is sometimes done by one person using a dolly. Navigating stairs, however, commonly requires two people. One person usually guides the unit from the top of the stairs while the other helps inch it down from bottom.
When safely in the building, place the heater precisely in its space, according to clearance guidelines. Turn off water from the building and inspect the plumbing to make sure each pipe properly reaches the top of the heater.

Plumbing

Line up water source pipes (commonly steel) to make sure a center-to-center match will allow the cold water inlet and hot water outlet to fit properly on the threaded connectors on top of the heater. Couplings and unions are often required to make a proper fit. If the unit runs on gas, the gas union is fitted to connect the gas line to the top of the heater (turn off gas before installing a union). Make sure to tape and connect all pipes so they don't leak.
If the heater is electric, turn off the home's circuit breaker and wire the heater to an electric meter, which acts as go-between for the unit and the main electric box. Wire and ground thermostats before turning the power and water back on. Gas heaters usually require a pilot light to be lit before operation. When all pipes are tested for leaks and the unit's power is on, the job is complete.