Each zone shall be provided with thermostatic setback controls that are controlled by either an automatic time clock or programmable control system.
- Zones that will be operated continuously.
- Zones with a full HVAC load demand not exceeding 6,800 Btu/h (2 kW) and having a readily accessible manual shutoff switch.
Thermostatic setback controls shall have the capability to set back or temporarily operate the system to maintain zone temperatures down to 55°F (13°C) or up to 85°F (29°C).
Automatic time clock or programmable controls shall be capable of starting and stopping the system for seven different daily schedules per week and retaining their programming and time setting during a loss of power for at least 10 hours. Additionally, the controls shall have a manual override that allows temporary operation of the system for up to 2 hours; a manually operated timer capable of being adjusted to operate the system for up to 2 hours; or an occupancy sensor.
Automatic start controls shall be provided for each HVAC system. The controls shall be capable of automatically adjusting the daily start time of the HVAC system in order to bring each space to the desired occupied temperature immediately prior to scheduled occupancy.
Where humidification, or dehumidification, or both is provided, the following shall be met:
- At least one humidity control device shall be provided for each humidity control system.
- Controls shall be provided capable of preventing simultaneous operation of humidification and dehumidification equipment.
- Zones served by desiccant systems, used with direct evaporative cooling in series.
- Systems serving zones where specific humidity levels are required, such as computer rooms, museums and hospitals, as approved by the building official.