lbl-srg · mwetter · Apr 14, 2026 · Apr 6, 2026 · Apr 6, 2026 · Apr 8, 2026
diff --git a/.travis.yml b/.travis.yml
@@ -47,6 +47,9 @@ env:
     - TEST_ARG="make test-dymola    PACKAGE=\"Buildings.{Air,Examples}\""
     - TEST_ARG="make test-openmodelica PACKAGE=\"Buildings.{Air,Examples}\""
     - TEST_ARG="make test-optimica  PACKAGE=\"Buildings.{Air,Examples}\""
+    - TEST_ARG="make test-dymola    PACKAGE=\"Buildings.Controls\""
+    - TEST_ARG="make test-openmodelica PACKAGE=\"Buildings.Controls\""
+    - TEST_ARG="make test-optimica  PACKAGE=\"Buildings.Controls\""
     - TEST_ARG="make test-dymola    PACKAGE=\"Buildings.ThermalZones.EnergyPlus_24_2_0\""
     - TEST_ARG="make test-openmodelica PACKAGE=\"Buildings.ThermalZones.EnergyPlus_24_2_0\""
     - TEST_ARG="make test-optimica  PACKAGE=\"Buildings.ThermalZones.EnergyPlus_24_2_0\""
@@ -95,9 +98,9 @@ env:
     - TEST_ARG="make test-dymola    PACKAGE=\"Buildings.Electrical\""
     - TEST_ARG="make test-openmodelica PACKAGE=\"Buildings.Electrical\""
     - TEST_ARG="make test-optimica  PACKAGE=\"Buildings.Electrical\""
-    - TEST_ARG="make test-dymola    PACKAGE=\"Buildings.{Airflow,BoundaryConditions,Controls}\""
-    - TEST_ARG="make test-openmodelica PACKAGE=\"Buildings.{Airflow,BoundaryConditions,Controls}\""
-    - TEST_ARG="make test-optimica  PACKAGE=\"Buildings.{Airflow,BoundaryConditions,Controls}\""
+    - TEST_ARG="make test-dymola    PACKAGE=\"Buildings.{Airflow,BoundaryConditions}\""
+    - TEST_ARG="make test-openmodelica PACKAGE=\"Buildings.{Airflow,BoundaryConditions}\""
+    - TEST_ARG="make test-optimica  PACKAGE=\"Buildings.{Airflow,BoundaryConditions}\""
     - TEST_ARG="make test-dymola    PACKAGE=\"Buildings.HeatTransfer\""
     - TEST_ARG="make test-openmodelica PACKAGE=\"Buildings.HeatTransfer\""
     - TEST_ARG="make test-optimica  PACKAGE=\"Buildings.HeatTransfer\""

diff --git a/Buildings/Controls/OBC/Utilities/PIDWithAutotuning/Relay/BaseClasses/TuningMonitor.mo b/Buildings/Controls/OBC/Utilities/PIDWithAutotuning/Relay/BaseClasses/TuningMonitor.mo
@@ -39,13 +39,17 @@ protected
   Buildings.Controls.OBC.CDL.Discrete.TriggeredSampler samAddtOntOff
     "Sample the minimum period when the minimum period is greater than 0"
     annotation (Placement(transformation(extent={{-40,-20},{-20,0}})));
-  Buildings.Controls.OBC.CDL.Reals.Greater tInc
+  Buildings.Controls.OBC.CDL.Reals.Greater tInc(
+    u1(unit="s"),
+    u2(unit="s"))
     "Check if either the length for the on period or the length for the off period increases after they both become positive"
     annotation (Placement(transformation(extent={{40,20},{60,40}})));
   Buildings.Controls.OBC.CDL.Reals.Add addtOntOff
     "Block that calculates the sum of the length for the on period and the length for the off period"
     annotation (Placement(transformation(extent={{-130,-20},{-110,0}})));
-  Buildings.Controls.OBC.CDL.Reals.Greater tDec
+  Buildings.Controls.OBC.CDL.Reals.Greater tDec(
+    u1(unit="s"),
+    u2(unit="s"))
     "Check if either the length for the on period or the length for the off period decreases after they both become positive"
     annotation (Placement(transformation(extent={{40,-70},{60,-50}})));
   Buildings.Controls.OBC.CDL.Logical.Or tCha
@@ -146,6 +150,11 @@ annotation (defaultComponentName = "tunMon",
     Documentation(revisions="<html>
 <ul>
 <li>
+March 31, 2026, by Michael Wetter:<br/>
+Corrected unit propagation error that causes Dymola 2026x to not show certain units.<br/>
+See <a href=\"https://github.com/ibpsa/modelica-ibpsa/issues/2100\">#2100</a>.
+</li>
+<li>
 September 20, 2023, by Sen Huang:<br/>
 First implementation.<br/>
 </li>

diff --git a/Buildings/DHC/Plants/Combined/Subsystems/Validation/ChillerHeatRecoveryGroup.mo b/Buildings/DHC/Plants/Combined/Subsystems/Validation/ChillerHeatRecoveryGroup.mo
@@ -246,7 +246,7 @@ model ChillerHeatRecoveryGroup
         origin={-30,-160})));
   Fluid.HeatExchangers.SensibleCooler_T disHeaWat(
     redeclare final package Medium = Medium,
-    final m_flow_nominal=THeaWatRet.k,
+    final m_flow_nominal=chi.mConWat_flow_nominal,
     final dp_nominal=0,
     energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial,
     tau=300,
@@ -264,7 +264,7 @@ model ChillerHeatRecoveryGroup
     annotation (Placement(transformation(extent={{80,-70},{100,-50}})));
   Fluid.HeatExchangers.SensibleCooler_T disConWatCon(
     redeclare final package Medium = Medium,
-    final m_flow_nominal=TConWatConSup.k,
+    final m_flow_nominal=chi.mConWat_flow_nominal,
     final dp_nominal=0,
     energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial,
     tau=300,
@@ -286,7 +286,7 @@ model ChillerHeatRecoveryGroup
     annotation (Placement(transformation(extent={{220,-30},{200,-10}})));
   Fluid.HeatExchangers.Heater_T disChiWat(
     redeclare final package Medium = Medium,
-    final m_flow_nominal=TChiWatRet.k,
+    final m_flow_nominal=chi.mChiWat_flow_nominal,
     final dp_nominal=0,
     energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial,
     tau=300,
@@ -468,6 +468,11 @@ in a configuration with two HRCs.
 </html>", revisions="<html>
 <ul>
 <li>
+March 31, 2026, by Michael Wetter:<br/>
+Corrected assignment of nominal mass flow rate.<br/>
+See <a href=\"https://github.com/ibpsa/modelica-ibpsa/issues/2100\">#2100</a>.
+</li>
+<li>
 February 24, 2023, by Antoine Gautier:<br/>
 First implementation.
 </li>

diff --git a/Buildings/Fluid/Actuators/BaseClasses/PartialTwoWayValve.mo b/Buildings/Fluid/Actuators/BaseClasses/PartialTwoWayValve.mo
@@ -22,7 +22,7 @@ partial model PartialTwoWayValve "Partial model for a two way valve"
   parameter Real kFixed(unit="", min=0) = if dpFixed_nominal > Modelica.Constants.eps
     then m_flow_nominal / sqrt(dpFixed_nominal) else 0
     "Flow coefficient of fixed resistance that may be in series with valve, k=m_flow/sqrt(dp), with unit=(kg.m)^(1/2).";
-  Real kVal(unit="1", min=Modelica.Constants.small)
+  Real kVal(unit="", min=Modelica.Constants.small)
     "Flow coefficient of valve, k=m_flow/sqrt(dp), with unit=(kg.m)^(1/2).";
   Real k(unit="", min=Modelica.Constants.small)
     "Flow coefficient of valve and pipe in series, k=m_flow/sqrt(dp), with unit=(kg.m)^(1/2).";
@@ -97,6 +97,11 @@ each valve opening characteristics has different parameters.
 revisions="<html>
 <ul>
 <li>
+March 31, 2026, by Michael Wetter:<br/>
+Corrected unit propagation error that causes Dymola 2026x to not show certain units.<br/>
+See <a href=\"https://github.com/ibpsa/modelica-ibpsa/issues/2100\">#2100</a>.
+</li>
+<li>
 January 19, 2026, by Jelger Jansen:<br/>
 Added unit 1 to parameter <code>kVal</code> to avoid FMU unit errors.<br/>
 This is for <a href=\"https://github.com/ibpsa/modelica-ibpsa/issues/2074\">#2074</a>.

diff --git a/Buildings/Fluid/CHPs/BaseClasses/EnergyConversion.mo b/Buildings/Fluid/CHPs/BaseClasses/EnergyConversion.mo
@@ -62,10 +62,10 @@ protected
     annotation (Placement(transformation(extent={{110,30},{130,50}})));
   Buildings.Fluid.CHPs.BaseClasses.EnergyConversionNormal opeModBas(final per=
         per) "Typical energy conversion mode"
-    annotation (Placement(transformation(extent={{-20,-10},{0,10}})));
+    annotation (Placement(transformation(extent={{-20,-40},{0,-20}})));
   Buildings.Fluid.CHPs.BaseClasses.EnergyConversionWarmUp opeModWarUpEngTem(
       final per=per) if not per.warmUpByTimeDelay "Warm-up by engine temperature"
-    annotation (Placement(transformation(extent={{-20,-60},{0,-40}})));
+    annotation (Placement(transformation(extent={{-20,-80},{0,-60}})));
   Buildings.Controls.OBC.CDL.Reals.Sources.Constant const(final k=0)
     "Zero constant"
     annotation (Placement(transformation(extent={{-100,60},{-80,80}})));
@@ -79,7 +79,7 @@ protected
     annotation (Placement(transformation(extent={{-100,90},{-80,110}})));
   Buildings.Controls.OBC.CDL.Reals.Switch switch2
     "Switch between warm-up and normal value"
-    annotation (Placement(transformation(extent={{80,70},{100,90}})));
+    annotation (Placement(transformation(extent={{80,82},{100,102}})));
   Buildings.Controls.OBC.CDL.Reals.Switch switch3
     "Switch between warm-up and normal value"
     annotation (Placement(transformation(extent={{80,10},{100,30}})));
@@ -92,34 +92,45 @@ protected
   Buildings.Controls.OBC.CDL.Reals.Sources.Constant PEleTimeDel(final k=0)
                if per.warmUpByTimeDelay
     "Zero power output in case of warm-up by time delay"
-    annotation (Placement(transformation(extent={{-20,90},{0,110}})));
+    annotation (Placement(transformation(extent={{-20,110},{0,130}})));
   Buildings.Controls.OBC.CDL.Logical.Sources.Constant delWarUp(
     final k=per.warmUpByTimeDelay) "Warm-up by time delay"
-    annotation (Placement(transformation(extent={{-100,-120},{-80,-100}})));
+    annotation (Placement(transformation(extent={{-100,-130},{-80,-110}})));
   Modelica.Blocks.Sources.BooleanExpression wamUpMod(
     final y=opeMod == CHPs.BaseClasses.Types.Mode.WarmUp)
     "Check whether warm-up mode is active"
     annotation (Placement(transformation(extent={{-100,30},{-80,50}})));
   Buildings.Controls.OBC.CDL.Logical.Not engTemWarUp
     "Warm-up based on engine temperature"
-    annotation (Placement(transformation(extent={{-60,-120},{-40,-100}})));
+    annotation (Placement(transformation(extent={{-60,-130},{-40,-110}})));
   Buildings.Controls.OBC.CDL.Logical.And and1
     "True if warm-up mode and warm-up based on engine temperature"
-    annotation (Placement(transformation(extent={{-20,-90},{0,-70}})));
-  Buildings.Controls.OBC.CDL.Reals.Sources.Constant dumTimDel(
-    final k=0) if per.warmUpByTimeDelay
-    "Set dummy value in case of warm-up by time delay"
-    annotation (Placement(transformation(extent={{-20,30},{0,50}})));
+    annotation (Placement(transformation(extent={{-20,-122},{0,-102}})));
+  Buildings.Controls.OBC.CDL.Reals.Sources.Constant dumTimDelFue(
+    final k=0,
+    y(unit="kg/s"))
+    if per.warmUpByTimeDelay "Set dummy value in case of warm-up by time delay"
+    annotation (Placement(transformation(extent={{-20,52},{0,72}})));
+  Controls.OBC.CDL.Reals.Sources.Constant dumTimDelAir(
+    final k=0,
+    y(unit="kg/s"))
+    if per.warmUpByTimeDelay "Set dummy value in case of warm-up by time delay"
+    annotation (Placement(transformation(extent={{-20,20},{0,40}})));
+  Controls.OBC.CDL.Reals.Sources.Constant dumTimDelGen(
+    final k=0,
+    y(unit="W"))
+    if per.warmUpByTimeDelay "Set dummy value in case of warm-up by time delay"
+    annotation (Placement(transformation(extent={{-20,-10},{0,10}})));
 
 equation
-  connect(opeModBas.mWat_flow, mWat_flow) annotation (Line(points={{-22,0},{-120,
-          0},{-120,20},{-160,20}},        color={0,0,127}));
-  connect(opeModBas.TWatIn, TWatIn) annotation (Line(points={{-22,-6},{-100,-6},
+  connect(opeModBas.mWat_flow, mWat_flow) annotation (Line(points={{-22,-30},{-110,
+          -30},{-110,20},{-160,20}},      color={0,0,127}));
+  connect(opeModBas.TWatIn, TWatIn) annotation (Line(points={{-22,-36},{-100,-36},
           {-100,-20},{-160,-20}},color={0,0,127}));
-  connect(opeModWarUpEngTem.TEng, TEng) annotation (Line(points={{-22,-58},{-110,
-          -58},{-110,-90},{-160,-90}},  color={0,0,127}));
-  connect(opeModWarUpEngTem.TWatIn, TWatIn) annotation (Line(points={{-22,-47},{
-          -100,-47},{-100,-20},{-160,-20}},
+  connect(opeModWarUpEngTem.TEng, TEng) annotation (Line(points={{-22,-78},{-110,
+          -78},{-110,-90},{-160,-90}},  color={0,0,127}));
+  connect(opeModWarUpEngTem.TWatIn, TWatIn) annotation (Line(points={{-22,-67},{
+          -100,-67},{-100,-20},{-160,-20}},
                                          color={0,0,127}));
   connect(const.y, switch.u3) annotation (Line(points={{-78,70},{-70,70},{-70,
           92},{-62,92}},
@@ -130,62 +141,65 @@ equation
   connect(booExp.y, switch.u2) annotation (Line(points={{-79,100},{-62,100}},
           color={255,0,255}));
   connect(switch.y, opeModBas.PEle) annotation (Line(points={{-38,100},{-30,100},
-          {-30,6},{-22,6}},  color={0,0,127}));
-  connect(opeModWarUpEngTem.PEleNet, switch2.u1) annotation (Line(points={{2,-42},
-          {20,-42},{20,88},{78,88}}, color={0,0,127}));
-  connect(switch2.y, PEleNet) annotation (Line(points={{102,80},{160,80}},
+          {-30,-24},{-22,-24}},
+                             color={0,0,127}));
+  connect(opeModWarUpEngTem.PEleNet, switch2.u1) annotation (Line(points={{2,-62},
+          {20,-62},{20,100},{78,100}},
+                                     color={0,0,127}));
+  connect(switch2.y, PEleNet) annotation (Line(points={{102,92},{120,92},{120,80},
+          {160,80}},
           color={0,0,127}));
   connect(switch3.y, mFue_flow) annotation (Line(points={{102,20},{160,20}},
           color={0,0,127}));
   connect(switch4.y, mAir_flow) annotation (Line(points={{102,-40},{160,-40}},
           color={0,0,127}));
   connect(switch5.y, QGen_flow)
     annotation (Line(points={{102,-100},{160,-100}}, color={0,0,127}));
-  connect(opeModBas.mFue_flow, switch3.u3) annotation (Line(points={{2,6},{60,6},
-          {60,12},{78,12}},     color={0,0,127}));
-  connect(opeModWarUpEngTem.mFue_flow, switch3.u1) annotation (Line(points={{2,-47},
-          {26,-47},{26,28},{78,28}}, color={0,0,127}));
-  connect(opeModBas.mAir_flow, switch4.u3) annotation (Line(points={{2,0},{60,0},
-          {60,-48},{78,-48}},      color={0,0,127}));
-  connect(opeModWarUpEngTem.mAir_flow, switch4.u1) annotation (Line(points={{2,-53},
-          {40,-53},{40,-32},{78,-32}},  color={0,0,127}));
-  connect(opeModWarUpEngTem.QGen_flow, switch5.u1) annotation (Line(points={{2,-58},
-          {32,-58},{32,-92},{78,-92}},      color={0,0,127}));
-  connect(opeModBas.QGen_flow, switch5.u3) annotation (Line(points={{2.2,-6},{54,
-          -6},{54,-108},{78,-108}},     color={0,0,127}));
+  connect(opeModBas.mFue_flow, switch3.u3) annotation (Line(points={{2,-24},{60,
+          -24},{60,12},{78,12}},color={0,0,127}));
+  connect(opeModWarUpEngTem.mFue_flow, switch3.u1) annotation (Line(points={{2,-67},
+          {26,-67},{26,28},{78,28}}, color={0,0,127}));
+  connect(opeModBas.mAir_flow, switch4.u3) annotation (Line(points={{2,-30},{60,
+          -30},{60,-48},{78,-48}}, color={0,0,127}));
+  connect(opeModWarUpEngTem.mAir_flow, switch4.u1) annotation (Line(points={{2,-73},
+          {40,-73},{40,-32},{78,-32}},  color={0,0,127}));
+  connect(opeModWarUpEngTem.QGen_flow, switch5.u1) annotation (Line(points={{2,-78},
+          {32,-78},{32,-92},{78,-92}},      color={0,0,127}));
+  connect(opeModBas.QGen_flow, switch5.u3) annotation (Line(points={{2.2,-36},{54,
+          -36},{54,-108},{78,-108}},    color={0,0,127}));
   connect(mWat_flow, opeModWarUpEngTem.mWat_flow) annotation (Line(points={{-160,20},
-          {-120,20},{-120,-42},{-22,-42}},     color={0,0,127}));
+          {-110,20},{-110,-62},{-22,-62}},     color={0,0,127}));
   connect(switch3.y, assFue.mFue_flow) annotation (Line(points={{102,20},{104,20},
           {104,40},{108,40}}, color={0,0,127}));
-  connect(PEleTimeDel.y, switch2.u1) annotation (Line(points={{2,100},{60,100},{
-          60,88},{78,88}}, color={0,0,127}));
+  connect(PEleTimeDel.y, switch2.u1) annotation (Line(points={{2,120},{60,120},{
+          60,100},{78,100}},
+                           color={0,0,127}));
   connect(switch.y, switch2.u3) annotation (Line(points={{-38,100},{-30,100},{-30,
-          72},{78,72}}, color={0,0,127}));
+          84},{78,84}}, color={0,0,127}));
   connect(TRoo, opeModWarUpEngTem.TRoo) annotation (Line(points={{-160,-60},{-120,
-          -60},{-120,-53},{-22,-53}},    color={0,0,127}));
+          -60},{-120,-73},{-22,-73}},    color={0,0,127}));
   connect(delWarUp.y, engTemWarUp.u)
-    annotation (Line(points={{-78,-110},{-62,-110}}, color={255,0,255}));
-  connect(engTemWarUp.y, and1.u2) annotation (Line(points={{-38,-110},{-30,-110},
-          {-30,-88},{-22,-88}}, color={255,0,255}));
-  connect(wamUpMod.y, and1.u1) annotation (Line(points={{-79,40},{-60,40},{-60,
-          -80},{-22,-80}},
+    annotation (Line(points={{-78,-120},{-62,-120}}, color={255,0,255}));
+  connect(engTemWarUp.y, and1.u2) annotation (Line(points={{-38,-120},{-22,-120}},
+                                color={255,0,255}));
+  connect(wamUpMod.y, and1.u1) annotation (Line(points={{-79,40},{-60,40},{-60,-100},
+          {-30,-100},{-30,-112},{-22,-112}},
                       color={255,0,255}));
-  connect(and1.y, switch3.u2) annotation (Line(points={{2,-80},{70,-80},{70,20},
+  connect(and1.y, switch3.u2) annotation (Line(points={{2,-112},{70,-112},{70,20},
           {78,20}}, color={255,0,255}));
-  connect(and1.y, switch4.u2) annotation (Line(points={{2,-80},{70,-80},{70,-40},
+  connect(and1.y, switch4.u2) annotation (Line(points={{2,-112},{70,-112},{70,-40},
           {78,-40}}, color={255,0,255}));
-  connect(and1.y, switch5.u2) annotation (Line(points={{2,-80},{70,-80},{70,-100},
+  connect(and1.y, switch5.u2) annotation (Line(points={{2,-112},{70,-112},{70,-100},
           {78,-100}}, color={255,0,255}));
-  connect(wamUpMod.y, switch2.u2) annotation (Line(points={{-79,40},{-60,40},{
-          -60,80},{78,80}},
-                        color={255,0,255}));
-  connect(dumTimDel.y, switch3.u1) annotation (Line(points={{2,40},{26,40},{26,28},
-          {78,28}}, color={0,0,127}));
-  connect(dumTimDel.y, switch4.u1) annotation (Line(points={{2,40},{40,40},{40,-32},
-          {78,-32}}, color={0,0,127}));
-  connect(dumTimDel.y, switch5.u1) annotation (Line(points={{2,40},{32,40},{32,-92},
-          {78,-92}}, color={0,0,127}));
+  connect(wamUpMod.y, switch2.u2) annotation (Line(points={{-79,40},{-60,40},{-60,
+          92},{78,92}}, color={255,0,255}));
+  connect(dumTimDelFue.y, switch3.u1) annotation (Line(points={{2,62},{26,62},{26,
+          28},{78,28}}, color={0,0,127}));
 
+  connect(switch4.u1, dumTimDelAir.y) annotation (Line(points={{78,-32},{40,-32},
+          {40,30},{2,30}}, color={0,0,127}));
+  connect(switch5.u1, dumTimDelGen.y) annotation (Line(points={{78,-92},{32,-92},
+          {32,0},{2,0}}, color={0,0,127}));
 annotation (
   defaultComponentName="eneCon",
   Diagram(coordinateSystem(extent={{-140,-140},{140,140}})),
@@ -208,6 +222,11 @@ combustion engines).
 </html>", revisions="<html>
 <ul>
 <li>
+March 31, 2026, by Michael Wetter:<br/>
+Corrected unit propagation error that causes Dymola 2026x to not show certain units.<br/>
+See <a href=\"https://github.com/ibpsa/modelica-ibpsa/issues/2100\">#2100</a>.
+</li>
+<li>
 April 8, 2020, by Antoine Gautier:<br/>
 Refactored implementation.
 </li>

diff --git a/Buildings/Fluid/Examples/Performance/BaseClasses/Example1.mo b/Buildings/Fluid/Examples/Performance/BaseClasses/Example1.mo
@@ -29,7 +29,10 @@ partial model Example1 "Example 1 partial model"
     annotation (Placement(transformation(extent={{-20,20},{0,40}})));
   Modelica.Blocks.Sources.Pulse pulse(period=1000) "Pulse input"
     annotation (Placement(transformation(extent={{-60,70},{-40,90}})));
-  Modelica.Blocks.Math.Gain gain(k=m_flow_nominal) "Gain for m_flow_nominal"
+  Modelica.Blocks.Math.Gain gain(
+    k=m_flow_nominal,
+    u(unit="1"),
+    y(unit="kg/s")) "Gain for m_flow_nominal"
     annotation (Placement(transformation(extent={{0,70},{20,90}})));
   Buildings.Fluid.Actuators.Valves.ThreeWayLinear val(
     redeclare package Medium = Medium,
@@ -109,6 +112,11 @@ and is created to avoid errors in the implementation of the two depending exampl
 </html>", revisions="<html>
 <ul>
 <li>
+March 31, 2026, by Michael Wetter:<br/>
+Corrected unit propagation error that causes Dymola 2026x to not show certain units.<br/>
+See <a href=\"https://github.com/ibpsa/modelica-ibpsa/issues/2100\">#2100</a>.
+</li>
+<li>
 May 8, 2017, by Michael Wetter:<br/>
 Updated heater model.<br/>
 This is for

diff --git a/Buildings/Fluid/Examples/ResistanceVolumeFlowReversal.mo b/Buildings/Fluid/Examples/ResistanceVolumeFlowReversal.mo
@@ -28,7 +28,10 @@ model ResistanceVolumeFlowReversal
     annotation (Placement(transformation(extent={{-40,-30},{-20,-10}})));
   Modelica.Blocks.Sources.Pulse pulse(period=1000) "Pulse input"
     annotation (Placement(transformation(extent={{-80,40},{-60,60}})));
-  Modelica.Blocks.Math.Gain gain(k=m_flow_nominal) "Gain for m_flow_nominal"
+  Modelica.Blocks.Math.Gain gain(
+    k=m_flow_nominal,
+    u(unit="1"),
+    y(unit="kg/s")) "Gain for m_flow_nominal"
     annotation (Placement(transformation(extent={{-40,40},{-20,60}})));
   Buildings.Fluid.Actuators.Valves.ThreeWayLinear val(
     redeclare package Medium = Medium,
@@ -103,7 +106,6 @@ equation
                                           color={0,127,255}));
     connect(senTem[i].port_b, val.port_3) annotation (Line(
        points={{10,-70},{0,-70},{0,-30}}, color={0,127,255}));
-
   end for;
 
   annotation (experiment(
@@ -164,6 +166,11 @@ Sizes after manipulation of the nonlinear systems: {1, 9, <b>1</b>}
 </html>", revisions="<html>
 <ul>
 <li>
+March 31, 2026, by Michael Wetter:<br/>
+Corrected unit propagation error that causes Dymola 2026x to not show certain units.<br/>
+See <a href=\"https://github.com/ibpsa/modelica-ibpsa/issues/2100\">#2100</a>.
+</li>
+<li>
 July 18, 2025, by Hongxiang Fu:<br/>
 Added two-port temperature sensors to replace <code>vol[:].T</code>
 from reference results.<br/>