(1) The installation of each appliance must conform to the manufacturer's installation instructions. The manufacturer's instructions must be attached to the appliance.

(2) Combustion air inlets and flue gas outlets must be listed as components of the appliance and must be completely separated. The required separation may be obtained by:

(a) The installation of direct vent system (sealed combustion system) appliances; or

(b) The installation of appliances within enclosures so that the appliance combustion system and venting system are separate from the interior atmosphere of the conversion vendor unit or medical unit. There must not be any door, removable access panel, or other opening into the enclosure from the inside of the conversion vendor unit or medical unit. Any openings for ducts, piping, wiring, etc., must be sealed.

(3) Ranges, cooktops, and ovens must not burn outside combustion air.