Final answer:
Water heaters not listed for outdoor installation but installed outdoors should be provided with weather protection. This protection includes structures like sheds or cabinets that shield from elements and ensure proper ventilation.
Step-by-step explanation:
When water heaters not listed for outside installation are installed outdoors, they shall be provided with weather protection.
This typically includes structures or enclosures that protect the water heater from direct contact with the elements such as rain, snow, and extreme temperatures.
Protection may take the form of a shed, cabinet, or a roof-like structure that shields the appliance while still ensuring adequate ventilation for proper operation and safety. Local building codes and manufacturers' instructions will often specify the type of weatherproofing required for outdoor water heater installation.