Under what circumstances may the roof not be recommended as a location for HVAC equipment?

The roof may not be recommended as a location for HVAC equipment primarily when load limits are exceeded. This consideration is crucial because roofs are designed to support a specific weight, which includes both the roofing materials and any additional loads, such as HVAC units. If an HVAC system's weight, combined with other factors like snow or equipment maintenance personnel, surpasses the roof's structural capacity, it can lead to severe structural damage or even catastrophic failure. Therefore, ensuring that the roof can handle the additional weight is key to maintaining the safety and integrity of the building.

Other factors mentioned, such as wind conditions or the color of the roof, do not directly pertain to the structural capabilities of the roof. Wind considerations are more relevant to the operational efficiency and stability of the HVAC equipment rather than structural limits. The coloration of the roof may influence heat retention but does not affect its capacity to support equipment. Additionally, the size of the equipment alone does not determine if it can be placed on the roof, as smaller equipment can still exceed load limits depending on the roof's characteristics. Hence, adherence to load limits is the primary reason for determining the suitability of the roof for HVAC equipment installation.