[EnergyPlus_Support] Warning: HVAC Maximum Interation exceeded for all HVAC loops

[x z <xs.zhang.2010@xxxxxxxxx>]

Hi All

 

I am running my model by using AHU (AirLoopHVAC, with heating and cooling coil, OA box and a VFD fan) and Uncontrolled ATU. I use SetpointManager:Scheduled to specify heating and cooling supply air temperature based on time (very rough control). All plant loops and system loops are autosized.I am receiving warning msg below:

 

How should fix this for my HVAC simulations?

 

    ** Warning ** SimHVAC: Maximum iterations (20) exceeded for all HVAC loops, at PT, 01/09 13:00 - 13:30
   **   ~~~   ** SimFlags=[TTTFFFFF] AirLoops[T],ZoneEq[T],NonZoneEq[T],PlantLoops[F],CondLoops[F],ElecCircuits[F],PlantDemandLoops[F],CondDemandLoops[F]..F=ok,T=fail
   **   ~~~   ** HVAC Tolerance Flags=[0000000] Enthalpy[0],MassFlow[0],HumRat[0],Pressure[0],FlowQual[0],Energy[0],Temp[0]..0=ok,1=fail
   **   ~~~   ** HVAC Tolerance Values, Most Recent listed first
   **   ~~~   ** HVAC EnthalpyTol=0.000, MassFlowTol=0.000, HumRatTol=0.0000, PressureTol=0
   **   ~~~   **      FlowQualTol=0.00, EnergyTol=0.000, TempTol=0.00
   **   ~~~   ** HVAC side outlet node=[330 - MIXER B:ZONE4 OUT NODE]
   **   ~~~   ** HVAC EnthalpyTol=0.000, MassFlowTol=0.000, HumRatTol=0.0000, PressureTol=0
   **   ~~~   **      FlowQualTol=0.00, EnergyTol=0.000, TempTol=0.00
   **   ~~~   ** HVAC side outlet node=[329 - MIXER B:ZONE1 OUT NODE]
   **   ~~~   ** HVAC EnthalpyTol=0.000, MassFlowTol=0.000, HumRatTol=0.0000, PressureTol=0
   **   ~~~   **      FlowQualTol=0.00, EnergyTol=0.000, TempTol=0.00
   **   ~~~   ** HVAC side outlet node=[328 - MIXER 7F:ZONE4 OUT NODE]
   **   ~~~   ** HVAC EnthalpyTol=0.000, MassFlowTol=0.000, HumRatTol=0.0000, PressureTol=0
   **   ~~~   **      FlowQualTol=0.00, EnergyTol=0.000, TempTol=0.00
   **   ~~~   ** HVAC side outlet node=[327 - MIXER 7F:ZONE2 OUT NODE]
   **   ~~~   ** HVAC EnthalpyTol=0.000, MassFlowTol=0.000, HumRatTol=0.0000, PressureTol=0
   **   ~~~   **      FlowQualTol=0.00, EnergyTol=0.000, TempTol=0.00
   **   ~~~   ** HVAC side outlet node=[326 - MIXER 6F:ZONE4 OUT NODE]
   **   ~~~   ** Plant Tolerance Flags=[00000000] Enthalpy[0],MassFlow[0],HumRat[0],Pressure[0],FlowQual[0],Energy[0],Temp[0],PlantFlowMassFlow[0]..0=ok,1=fail
   **   ~~~   ** Plant Tolerance Values, Most Recent listed first
   **   ~~~   ** Plant EnthalpyTol=0.000, MassFlowTol=0.000, HumRatTol=0.0000, PressureTol=0
   **   ~~~   **      FlowQualTol=0.00, EnergyTol=0.000, TempTol=0.00
   **   ~~~   ** Plant side outlet node=[177 - CHILLED WATER LOOP CNDW DEMAND OUTLET]
   **   ~~~   ** Plant EnthalpyTol=0.000, MassFlowTol=0.000, HumRatTol=0.0000, PressureTol=0
   **   ~~~   **      FlowQualTol=0.00, EnergyTol=0.000, TempTol=0.00
   **   ~~~   ** Plant side outlet node=[172 - CHILLED WATER LOOP CNDW DEMAND INLET]
   **   ~~~   ** Plant EnthalpyTol=0.000, MassFlowTol=0.000, HumRatTol=0.0000, PressureTol=0
   **   ~~~   **      FlowQualTol=0.00, EnergyTol=-15921995.331, TempTol=20.15
   **   ~~~   ** Plant side outlet node=[165 - CHILLED WATER LOOP CHW DEMAND OUTLET]
   **   ~~~   ** Plant EnthalpyTol=0.000, MassFlowTol=0.000, HumRatTol=0.0000, PressureTol=0
   **   ~~~   **      FlowQualTol=0.00, EnergyTol=0.000, TempTol=0.00
   **   ~~~   ** Plant side outlet node=[146 - HOT WATER LOOP HW DEMAND OUTLET]
   **   ~~~   ** Plant EnthalpyTol=0.000, MassFlowTol=189.003, HumRatTol=0.0000, PressureTol=0
   **   ~~~   **      FlowQualTol=189.00, EnergyTol=5704038.440, TempTol=0.00
   **   ~~~   ** Plant side outlet node=[160 - CHILLED WATER LOOP CHW DEMAND INLET]
   **   ~~~   ** Plant Flow Tolerance Values, Most Recent listed first
   **   ~~~   ** PlantFlowFlowTol=0.000
   **   ~~~   ** PlantFlowFlowTol=0.000
   **   ~~~   ** PlantFlowFlowTol=0.000
   **   ~~~   ** PlantFlowFlowTol=189.003
   **   ~~~   ** PlantFlowFlowTol=0.000

 

Thanks for your answer.

Have a wonderful weekend.

 

Zhang

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