diff --git a/AixLib/DataBase/Boiler/General/BoilerTwoPointBaseDataDefinition.mo b/AixLib/DataBase/Boiler/General/BoilerTwoPointBaseDataDefinition.mo
index 2737190e3a..458dc9a1b1 100644
--- a/AixLib/DataBase/Boiler/General/BoilerTwoPointBaseDataDefinition.mo
+++ b/AixLib/DataBase/Boiler/General/BoilerTwoPointBaseDataDefinition.mo
@@ -10,7 +10,9 @@ record BoilerTwoPointBaseDataDefinition
     "Water volume of boiler";
   parameter Real pressureDrop
     "Pressure drop coefficient, delta_p[Pa] = PD*Q_flow[m^3/s]^2";
-  parameter SI.Power Q_nom
+      parameter SI.Power Q_flowFuel_nominal
+    "Nominal fuel power / firing power, refering to net (inferior) calorific value";
+  parameter SI.Power Q_flow_nominal
     "Nominal heat power / thermal load, refering to net (inferior) calorific value";
   parameter SI.Power Q_min
     "Minimal heat power / thermal load, refering to net (inferior) calorific value";
diff --git a/AixLib/DataBase/Boiler/General/Boiler_Virtual_1kW.mo b/AixLib/DataBase/Boiler/General/Boiler_Virtual_1kW.mo
index 9f95660d0f..35403852fb 100644
--- a/AixLib/DataBase/Boiler/General/Boiler_Virtual_1kW.mo
+++ b/AixLib/DataBase/Boiler/General/Boiler_Virtual_1kW.mo
@@ -4,7 +4,8 @@ record Boiler_Virtual_1kW "Boiler virtual 1kW"
     name="VirtualBoiler_1kW",
     volume=0.00076,
     pressureDrop=10218000000.0,
-    Q_nom=1000,
+    Q_flowFuel_nominal=1000,
+    Q_flow_nominal=900,
     Q_min=100,
     eta=[0.3,0.93; 1.0,0.93]);
     annotation (Documentation(revisions="<html><ul>
diff --git a/AixLib/DataBase/Boiler/General/Boiler_Vitocrossal200_311kW.mo b/AixLib/DataBase/Boiler/General/Boiler_Vitocrossal200_311kW.mo
index 9ddcdea1d6..a8601d1e24 100644
--- a/AixLib/DataBase/Boiler/General/Boiler_Vitocrossal200_311kW.mo
+++ b/AixLib/DataBase/Boiler/General/Boiler_Vitocrossal200_311kW.mo
@@ -5,7 +5,8 @@ record Boiler_Vitocrossal200_311kW
     name="Vitocrossal200_311kW",
     volume=279/1000,
     pressureDrop = 4000/(7.79e-3)^2,
-    Q_nom = 326000,
+    Q_flowFuel_nominal = 326000,
+    Q_flow_nominal=311000,
     Q_min = 326000*0.33,
     eta = [0.3, (0.973+0.989)/2;
            0.4, (0.960+0.981)/2;
diff --git a/AixLib/DataBase/Boiler/General/Boiler_Vitodens300W_13kW.mo b/AixLib/DataBase/Boiler/General/Boiler_Vitodens300W_11kW.mo
similarity index 69%
rename from AixLib/DataBase/Boiler/General/Boiler_Vitodens300W_13kW.mo
rename to AixLib/DataBase/Boiler/General/Boiler_Vitodens300W_11kW.mo
index e8b8171be8..3ae2487ca6 100644
--- a/AixLib/DataBase/Boiler/General/Boiler_Vitodens300W_13kW.mo
+++ b/AixLib/DataBase/Boiler/General/Boiler_Vitodens300W_11kW.mo
@@ -1,13 +1,14 @@
 within AixLib.DataBase.Boiler.General;
-record Boiler_Vitodens300W_13kW
-  "Condesing boiler Viessmann Vitodens 300W 13kW, for Tv/Tr = 50/30 degC"
+record Boiler_Vitodens300W_11kW
+  "Condesing boiler Viessmann Vitodens 300W 11kW, for Tv/Tr = 50/30 degC"
   extends BoilerTwoPointBaseDataDefinition(
-    name="Vitodens300W_13kW",
-    volume=0.0076,
-    pressureDrop=10218000000.0,
-    Q_nom=16700,
+    name="Vitodens300W_11kW",
+    volume=0.0042,
+    pressureDrop=17025510099,
+    Q_flowFuel_nominal=10300,
+    Q_flow_nominal=11000,
     Q_min=3600,
-    eta=[0.3,1.061; 1.0,0.954]);
+    eta=[0.173,1.056; 1.0,1.068]);
   annotation (Documentation(revisions="<html><ul>
   <li>
     <i>December 08, 2016&#160;</i> by Moritz Lauster:<br/>
@@ -35,4 +36,4 @@ record Boiler_Vitodens300W_13kW
   </li>
 </ul>
 </html>"));
-end Boiler_Vitodens300W_13kW;
+end Boiler_Vitodens300W_11kW;
diff --git a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_11kW.mo b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_11kW.mo
index a425d5cb42..45f3760351 100644
--- a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_11kW.mo
+++ b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_11kW.mo
@@ -4,7 +4,8 @@ record Boiler_Vitogas200F_11kW "Gas-fired boiler Viessmann Vitogas200-F 11kW"
     name="Vitogas200F_11kW",
     volume=0.0076,
     pressureDrop=10218000000.0,
-    Q_nom=12100,
+    Q_flowFuel_nominal=12100,
+    Q_flow_nominal=11000,
     Q_min=3630,
     eta=[0.3,0.93; 1.0,0.93]);
   annotation (Documentation(revisions="<html><ul>
diff --git a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_15kW.mo b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_15kW.mo
index 3cb663d71f..b3c8c3224a 100644
--- a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_15kW.mo
+++ b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_15kW.mo
@@ -4,7 +4,8 @@ record Boiler_Vitogas200F_15kW "Gas-fired boiler Viessmann Vitogas200-F 15kW"
     name="Vitogas200F_15kW",
     volume=0.0076,
     pressureDrop=10218000000.0,
-    Q_nom=16600,
+    Q_flowFuel_nominal=16600,
+    Q_flow_nominal=15000,
     Q_min=4980,
     eta=[0.3,0.93; 1.0,0.93]);
     annotation (Documentation(revisions="<html><ul>
diff --git a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_18kW.mo b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_18kW.mo
index f18ae7264f..ca0e121733 100644
--- a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_18kW.mo
+++ b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_18kW.mo
@@ -4,9 +4,10 @@ record Boiler_Vitogas200F_18kW "Gas-fired boiler Viessmann Vitogas200-F 18kW"
     name="Vitogas200F_18kW",
     volume=0.0097,
     pressureDrop=7853000000.0,
-    Q_nom=19900,
+    Q_flowFuel_nominal=19900,
+    Q_flow_nominal=18000,
     Q_min=5970,
-    eta=[0.3,0.93; 1.0,0.93]);
+    eta=[0.3,0.885; 1.0,0.885]);
     annotation (Documentation(revisions="<html><ul>
   <li>
     <i>December 08, 2016&#160;</i> by Moritz Lauster:<br/>
diff --git a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_22kW.mo b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_22kW.mo
index 713234d395..6500ad20ce 100644
--- a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_22kW.mo
+++ b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_22kW.mo
@@ -4,7 +4,8 @@ record Boiler_Vitogas200F_22kW "Gas-fired boiler Viessmann Vitogas200-F 22kW"
     name="Vitogas200F_22kW",
     volume=0.0097,
     pressureDrop=7853000000.0,
-    Q_nom=24300,
+    Q_flowFuel_nominal=24300,
+    Q_flow_nominal=22000,
     Q_min=7290,
     eta=[0.3,0.93; 1.0,0.93]);
     annotation (Documentation(revisions="<html><ul>
diff --git a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_29kW.mo b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_29kW.mo
index f85273c7c7..ab99e38a84 100644
--- a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_29kW.mo
+++ b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_29kW.mo
@@ -4,7 +4,8 @@ record Boiler_Vitogas200F_29kW "Gas-fired boiler Viessmann Vitogas200-F 29kW"
     name="Vitogas200F_29kW",
     volume=0.0117,
     pressureDrop=6411000000.0,
-    Q_nom=32000,
+    Q_flowFuel_nominal=32000,
+    Q_flow_nominal=29000,
     Q_min=9600,
     eta=[0.3,0.93; 1.0,0.93]);
     annotation (Documentation(revisions="<html><ul>
diff --git a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_35kW.mo b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_35kW.mo
index 5a636c087d..5dc68dee19 100644
--- a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_35kW.mo
+++ b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_35kW.mo
@@ -4,7 +4,8 @@ record Boiler_Vitogas200F_35kW "Gas-fired boiler Viessmann Vitogas200-F 35kW"
     name="Vitogas200F_35kW",
     volume=0.0138,
     pressureDrop=4009000000.0,
-    Q_nom=38600,
+    Q_flowFuel_nominal=38600,
+    Q_flow_nominal=35000,
     Q_min=11580,
     eta=[0.3,0.93; 1.0,0.93]);
     annotation (Documentation(revisions="<html><ul>
diff --git a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_42kW.mo b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_42kW.mo
index 42681ac07d..b90e66ceba 100644
--- a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_42kW.mo
+++ b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_42kW.mo
@@ -4,7 +4,8 @@ record Boiler_Vitogas200F_42kW "Gas-fired boiler Viessmann Vitogas200-F 42kW"
     name="Vitogas200F_42kW",
     volume=0.0159,
     pressureDrop=4009000000.0,
-    Q_nom=46400,
+    Q_flowFuel_nominal=46400,
+    Q_flow_nominal=42000,
     Q_min=13920,
     eta=[0.3,0.93; 1.0,0.93]);
     annotation (Documentation(revisions="<html><ul>
diff --git a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_48kW.mo b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_48kW.mo
index cbf9ee50d4..6b8565ffdb 100644
--- a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_48kW.mo
+++ b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_48kW.mo
@@ -4,7 +4,8 @@ record Boiler_Vitogas200F_48kW "Gas-fired boiler Viessmann Vitogas200-F 48kW"
     name="Vitogas200F_48kW",
     volume=0.0159,
     pressureDrop=3240000000.0,
-    Q_nom=53000,
+    Q_flowFuel_nominal=53000,
+    Q_flow_nominal=48000,
     Q_min=15900,
     eta=[0.3,0.93; 1.0,0.93]);
     annotation (Documentation(revisions="<html><ul>
diff --git a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_60kW.mo b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_60kW.mo
index 7222ae5cf0..b04f38b68e 100644
--- a/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_60kW.mo
+++ b/AixLib/DataBase/Boiler/General/Boiler_Vitogas200F_60kW.mo
@@ -4,7 +4,8 @@ record Boiler_Vitogas200F_60kW "Gas-fired boiler Viessmann Vitogas200-F 60kW"
     name="Vitogas200F_60kW",
     volume=0.0159,
     pressureDrop=3240000000.0,
-    Q_nom=66200,
+    Q_flowFuel_nominal=66200,
+    Q_flow_nominal=60000,
     Q_min=19860,
     eta=[0.3,0.93; 1.0,0.93]);
     annotation (Documentation(revisions="<html><ul>
diff --git a/AixLib/Fluid/BoilerCHP/BoilerNoControl.mo b/AixLib/Fluid/BoilerCHP/BoilerNoControl.mo
index fab8e9103d..5ffb9ba656 100644
--- a/AixLib/Fluid/BoilerCHP/BoilerNoControl.mo
+++ b/AixLib/Fluid/BoilerCHP/BoilerNoControl.mo
@@ -13,9 +13,12 @@ model BoilerNoControl "Boiler model with physics only"
     "Heat capacity of metal (J/K)";
   parameter Modelica.Units.SI.Volume V=paramBoiler.volume "Volume";
 
-  parameter Modelica.Units.SI.Power Q_nom=paramBoiler.Q_nom
+    parameter Modelica.Units.SI.Power Q_nom=paramBoiler.Q_flow_nominal
     "Nominal heating power";
 
+  parameter Modelica.Units.SI.Power Q_flowFuel_nominal=paramBoiler.Q_flowFuel_nominal
+    "Nominal firing power";
+
   Modelica.Thermal.HeatTransfer.Components.HeatCapacitor internalCapacity(
       final C=C, T(start=T_start)) "Boiler thermal capacity (dry weight)"
     annotation (Placement(transformation(
@@ -33,8 +36,8 @@ model BoilerNoControl "Boiler model with physics only"
   Modelica.Blocks.Nonlinear.Limiter limiter(final uMax=1, final uMin=0)
     "Limits the rel power between 0 and 1"
     annotation (Placement(transformation(extent={{-80,60},{-60,80}})));
-  Modelica.Blocks.Sources.RealExpression NominalGasConsumption(final y=Q_nom/
-        max(etaLoadBased[:,2]*max(etaTempBased[:,2])))
+  Modelica.Blocks.Sources.RealExpression NominalGasConsumption(final y=
+        Q_flowFuel_nominal)
     "Nominal gas power"
     annotation (Placement(transformation(extent={{-62,88},{-34,104}})));
   Modelica.Blocks.Interfaces.RealOutput fuelPower
