Daikin MicroTech III DPS Installation And Maintenance Manual

Contents

Daikin MicroTech III DPS Installation And Maintenance Manual Manual pdf 47 page image

Operator’s Guidewww DaikinApplied com47 OM 1263 • MICROTECH UNIT CONTROLLEROperator’s GuideThe following “Operator’s Guide” sections provide informationregarding the day-to-day operation of the MicroTech IIIUnit Controller Topics covered are such common tasks asscheduling, displaying and clearing alarms, and setting thecontroller for manual operationFigure 13: State DiagramThe transition from any operating state to another is graphicallyrepresented in this figure. With a “start up” command froman Off State the unit will always go into the “Start Up” state ofoperation for 3 minutes (adjustable) Next, it will transition intothe “Recirculation” state of operation for another 3 minutes(adjustable) before finally going into the Fan Only state ofoperation Then, based on sensor inputs it will go into anyof the 4 remaining states of operation - heating, cooling,economizer, or minimum discharge air heating.Determining Unit State(See page 58 for more information)The unit will operate in one of eight operating states Thecurrent state will be displayed by the Unit State parameter inthe system summary menuIn the OFF state, all heating, cooling, and fans are OFF Thealarm output indicates the type of alarm, if any, that is activeIn the start up state, the Fan Operation output is turned ON toallow shut off dampers to be opened before any the supply fanis turned ON The outdoor air dampers remain closedThe supply fan is turned ON when the unit enters theRecirculation state The supply fan in VAV units is controlledas described in the Supply Fan Capacity Control section, page20 The outdoor dampers remain closedA separate morning warm-up state is not provided, but anedited ZeroOATime is used to keep the outside air damperclosed when the unit first starts. The Minimum OA Position isset to zero as long as the as the fan has been on for less thanthe ZeroOATimeDAT Control units have a MWU set point availableThe Minimum OA Position is set to zero as long as the as thefan has been on for less than the ZeroOATime This allows theReturn Air type units to cool down the space with mechanicalcooling or to warm up the space with the dampers closed If theZeroOATime is set correctly, the OA dampers will be open onlyduring occupied periods When Optimum Start is used Zero OATime is set equal to the time to occupancy when the unit startsso that the OA dampers will open at occupancy timeNeither heating nor cooling is provided when the unit is in thefan only state, with the exception of when dehumidificationis active The outdoor dampers are opened to the minimumposition in this state when the fan on time exceeds the ZeroOA TimeIn the other four states, temperature is controlled as describein the appropriate sections of this document These states areMinimum DAT, Heating, Economizer, and Cooling. The outdoordampers are opened to at least the minimum position in thesestates when the fan on time exceeds the Zero OA TimeOff Operating StateIn the OFF operating state the fans are OFF, the outside airdampers are closed and any variable speed supply air fan’sare driven to 0% Cooling and heating are disabled The unitis in the OFF state when it is not enabled, or when it is in theunoccupied mode with no call for unoccupied operation referto “Determining Unit Status” on page 57 for reasons the unitcan be disabled