Which of the following is not a benefit of direct digital control thermostat systems?

The option indicating that it converts inexpensively from pneumatic control is not considered a benefit of direct digital control (DDC) thermostat systems because the transition from pneumatic systems to DDC systems often involves significant costs and a comprehensive upgrade of infrastructure. This includes not only the costs of new equipment but also potential modifications to existing systems to integrate modern technology.

On the other hand, the benefits of quick response times, accurate readings, and the ability to issue maintenance alerts highlight the essential features of DDC systems. These systems provide rapid adjustments to temperature settings in response to changes in the environment, which increases energy efficiency and comfort levels. Accurate readings are crucial for maintaining the desired indoor climate and ensuring that the HVAC system operates optimally. Additionally, the capability to provide maintenance alerts helps in proactive management and reduces downtime by alerting facility managers about necessary repairs or maintenance before issues escalate. Thus, option A does not align with the main advantages offered by DDC systems.