This is called a common vent configuration.
Getting water heater into attic.
Raise the heater up have a second person control the motion and guide it through the access point.
Take a close look at any plumbing and gas fittings in the vicinity of the water heater for wet spots or signs of rust and corrosion and be sure to check the outer tank for any signs of rust.
Use a rope to attach to the ratchet strap 3.
Another option is to choose a tankless water heaterto be installed in your attic.
Another reason why installing a gas water heater in the attic is not a good idea is if the tank or any connection leaks.
Go up into the attic and stand on the rafters not the stairs 4.
Most importantly along the seam of the tank.
The water will flood rooms in the lower level and do the damage.
Be sure to get up into your attic water heater at least twice a year to check your water heater for any sign of leaks.
How to hoist 50 gallon water heater into attic.
Use a cargo tie down ratcheting strap around the heater 2.
In many cases the exhaust from the larger appliance heats up the common vent improving the flow of the water heater vent.
This is far less expensive than your water heater leaking and causing thousands of dollars worth of water damage.