Which type of heater shall not be installed in combustible walls unless specified?

Wall-type room heaters are specifically designed for installation in areas where there may be combustible materials, but they require careful adherence to safety regulations and specifications when it comes to their installation. These heaters generate considerable heat and can pose a fire risk if placed too close to combustible walls without appropriate safety measures.

Manufacturers often provide detailed guidelines for the safe installation of such heaters, emphasizing the importance of maintaining a minimum clearance from combustible materials. Specific certification standards may also stipulate the conditions under which wall-type room heaters can be installed in such environments. By specifying that these heaters should not be installed in combustible walls unless explicitly detailed in the manufacturer's instructions or local codes, safety is prioritized to prevent any potential hazards associated with excessive heat buildup and combustion.

The other types of heaters generally have different installation guidelines and clearance requirements based on their design and function, which may allow for safer installation in proximity to combustible materials under certain circumstances.