hVac controls guide for Plans examiners and Building inspectors

Control Requirements for All SystemsThermostatic Control of Heating and CoolingThermostatic controls are required in each conditioned building zone. These devices must be capable ofsetting the zone’s target temperature for heating and cooling. They must also prevent simultaneous heatingand cooling of the zone and allow for a range of allowable temperatures, known as a deadband, in whichneither heating nor cooling is provided. Finally, the thermostatic controls must allow the system to scheduleunoccupied periods and occupied periods, allowing for a system start up period between. During theunoccupied period, heating and cooling target temperatures can be set back to conserve energy by allowing agreater range of space temperatures.Plan ReviewSuggested Compliance Check(s):• Check mechanical floor plans to verify that there is at least onethermostat per distinct occupancy area (figure 1).• Review the mechanical floor plans and mechanical schedule to locate control sequences and verifythat the design engineer has specified deadband, set back and scheduling capabilities (figures 2-4).** If the building is equipped with a building automation system (BAS), then these capabilities will most likely beprovided by the BAS. The BAS specifications or manual should indicate that the required capabilities are present.Control Requirements for All Systems 11