Index: firmware/App/Modes/Dialysis.c
===================================================================
diff -u -r2e6c750c202b7361d79488ce383e34f380e75413 -r108abddcbf729f7435073116191cd3903261df8f
--- firmware/App/Modes/Dialysis.c	(.../Dialysis.c)	(revision 2e6c750c202b7361d79488ce383e34f380e75413)
+++ firmware/App/Modes/Dialysis.c	(.../Dialysis.c)	(revision 108abddcbf729f7435073116191cd3903261df8f)
@@ -175,7 +175,7 @@
     setDialOutUFVolumes( refUFVolume, measUFVolume );
     setBloodPumpTargetFlowRate( setBloodFlowRate, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_OPEN_LOOP );
     setDialInPumpTargetFlowRate( setDialysateFlowRate, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_OPEN_LOOP );
-    setDialOutPumpTargetRate( setDialysateFlowRate, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_CLOSED_LOOP );
+    setDialOutPumpTargetRate( setDialysateFlowRate + FLOAT_TO_INT_WITH_ROUND( setUFRate ), MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_CLOSED_LOOP );
     // TODO - Heparin pump
 }
 
@@ -198,6 +198,64 @@
 
 /*********************************************************************//**
  * @brief
+ * The pauseUF function pauses ultrafiltration.
+ * @details
+ * Inputs : currentDialysisState, currentUFState
+ * Outputs : currentUFState, outlet pump set point
+ * @return TRUE if pause successful, FALSE if not
+ *************************************************************************/
+BOOL pauseUF( void )
+{
+    BOOL result = FALSE;
+
+    if ( ( DIALYSIS_UF_STATE == currentDialysisState ) && ( UF_RUNNING_STATE == currentUFState ) )
+    {
+        // set outlet pump to dialysate rate
+        result = setDialOutPumpTargetRate( setDialysateFlowRate, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_CLOSED_LOOP );
+
+        if ( TRUE == result )
+        {
+            // go to UF paused state
+            currentUFState = UF_PAUSED_STATE;
+        }
+    }
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
+ * The resumeUF function resumes ultrafiltration.
+ * @details
+ * Inputs : currentDialysisState, currentUFState
+ * Outputs : currentUFState, outlet pump set point
+ * @return TRUE if resume successful, FALSE if not
+ *************************************************************************/
+BOOL resumeUF( void )
+{
+    BOOL result = FALSE;
+
+    if ( ( DIALYSIS_UF_STATE == currentDialysisState ) && ( UF_PAUSED_STATE == currentUFState ) )
+    {
+        S32 inletPumpRate = getTargetDialInFlowRate();
+
+        // set outlet pump to dialysate rate + set UF rate
+        result = setDialOutPumpTargetRate( setDialysateFlowRate + FLOAT_TO_INT_WITH_ROUND( setUFRate ), MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_CLOSED_LOOP );
+
+        if ( TRUE == result )
+        {
+            // restart UF time accumulation for reference volume calculation
+            lastUFTimeStamp = getMSTimerCount();
+            // go to UF paused state
+            currentUFState = UF_RUNNING_STATE;
+        }
+    }
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
  * The execDialysis function executes the Dialysis sub-mode state machine.
  * @details
  * Inputs : currentDialysisState
@@ -331,7 +389,7 @@
     // TODO - test code - remove later
     if ( TRUE == isStopButtonPressed() )
     {
-        lastUFTimeStamp = getMSTimerCount();  // restart UF time accumulation
+        resumeUF();
         result = UF_RUNNING_STATE;
     }
 
@@ -370,6 +428,7 @@
     // TODO - test code - remove later
     if ( TRUE == isStopButtonPressed() )
     {
+        pauseUF();
         result = UF_PAUSED_STATE;
     }