Water heater timer for conventional gas water heater/

HomeObjective> save 6-8% energy in every home in US >> Big Plan, Simple Idea
Below is a Gear-motor-prototype explained in 4 steps

Step 1: Timer turns motor on for 20 seconds > motor rotates gears > largest gear has metal shaft (marked with red line) > this shaft will fit over gas valve on water heater
Step 2: The motor shown above will work with gas valve on residential water heater shown below

Note gas valve can be set to 'vacation'  > vacation will stop water from being heated throughout day when nobody is home > and again at night when people are sleeping
Step 3: Illustrated below, the black knob pulls off of stem [marked with red line]. The stem sticks up from gas valve about 1/2"

The stem has a hex bolt and a 'key' sticking out [at 3:30 position]
Step 4: The gear motor shaft will fit over hex bolt and key [enlarged below]

Gear motor will be controlled by a wall-mounted timer. When gear motor is turned on, water heater is set to vacation > this will save energy when nobody needs hot water

When gear motor is turned on again, water heater is set to thermostatic setting > water  resumes heating again

Use timer to best advantage requires planning

For example > it takes 1/2 hour to heat enough hot water for shower > it takes 1 hour to heat enough water for bath > and it takes 20 minutes to heat enough hot water to wash up