Options D19 and D21

The control system consists of a factory-installed system controller, a conventional field-installed thermostat and/or optional field-installed space-mounted thermostat with up to five space-averaging sensors (option CL78), and an optional field-installed wall-mounted or handheld remote display (option RB5). The control system operates the supply fan, dampers, cooling, and heating to maintain a set of discharge air temperature control setpoints and allows for complete access to unit test features, schedules, discharge air setpoints, fan control, alarms, and other unit operational setpoints.