The provisions of this chapter and any regulations adopted pursuant thereto do not apply to a water heater if, with regard to the water heater, none of the following limitations is exceeded:

1.  An input of heat of 199,999 British thermal units per hour (58,600 watts).

2.  A water temperature of 210 degrees Fahrenheit (99 degrees Centigrade).

3.  A water capacity of 120 gallons (450 liters).