Index: firmware/App/Modes/ModeTreatment.c
===================================================================
diff -u -rb687ab5673dc5da53537f538056ea12842b3f6ce -re2cf7feff54dad3fc5be72619fa64b5421fc6f9f
--- firmware/App/Modes/ModeTreatment.c	(.../ModeTreatment.c)	(revision b687ab5673dc5da53537f538056ea12842b3f6ce)
+++ firmware/App/Modes/ModeTreatment.c	(.../ModeTreatment.c)	(revision e2cf7feff54dad3fc5be72619fa64b5421fc6f9f)
@@ -8,7 +8,7 @@
 * @file    ModeTreatment.c
 *
 * @author  (last)      Darren Cox
-* @date    (last)      23-Aug-2023
+* @date    (last)      19-Sep-2023
 *
 * @author  (original)  Dara Navaei
 * @date    (original)  05-Nov-2019
@@ -1036,6 +1036,7 @@
             setTreatmentParameterF32( TREATMENT_PARAM_UF_VOLUME, ( presMaxUFVolumeML / (F32)ML_PER_LITER ) );
             setTreatmentParameterU32( TREATMENT_PARAM_TREATMENT_DURATION, ( presTreatmentTimeSecs / SEC_PER_MIN ) );
             setDialysisParams( getTreatmentParameterU32( TREATMENT_PARAM_BLOOD_FLOW ), getTreatmentParameterU32( TREATMENT_PARAM_DIALYSATE_FLOW ), presMaxUFVolumeML, presUFRate );
+            signalInitiatePressureStabilization( USE_NORMAL_STABILIZATION_PERIOD );
         }
         else
         {
@@ -1091,7 +1092,7 @@
  * @details Inputs: current operating mode, treatment states and parameters
  * @details Outputs: response message sent
  * @param uFVolume New ultrafiltration volume requested by the user
- * @return TRUE if new UF voluem is valid, FALSE if not.
+ * @return TRUE if new UF volume is valid, FALSE if not.
  *************************************************************************/
 BOOL verifyUFSettingsChange( F32 uFVolume )
 {
@@ -1103,6 +1104,7 @@
     S32 txSecRem = CALC_TREAT_TIME_REMAINING_IN_SECS();
     S32 txMinEla = CALC_ELAPSED_TREAT_TIME_IN_SECS() / SEC_PER_MIN;
     F32 txMinRem = (F32)txSecRem / (F32)SEC_PER_MIN;
+    F32 colUFVol = getUltrafiltrationReferenceVolume();                                          // How much UF volume have we taken so far?
 
     // Reset pending UF/time settings changes to current values in case request is rejected
     pendingUFVolumeChange = presMaxUFVolumeML;
@@ -1112,12 +1114,11 @@
     // Check if we are in an appropriate treatment state for settings adjustment
     if ( ( MODE_TREA == currMode ) &&
          ( currentTreatmentState > TREATMENT_START_STATE ) && ( currentTreatmentState < TREATMENT_END_STATE ) &&
-         ( uFVolume <= MAX_UF_VOLUME_ML ) &&
+         ( uFVolume <= MAX_UF_VOLUME_ML ) && ( uFVolume > colUFVol ) &&
          ( CALC_TREAT_TIME_REMAINING_IN_SECS() >= PREVENT_UF_VOL_CHANGE_IF_NEARLY_DONE_SEC ) )
     {
         DIALYSIS_STATE_T currDialysisState = getDialysisState();
         UF_STATE_T currUFState = getUltrafiltrationState();
-        F32 colUFVol = getUltrafiltrationReferenceVolume();                                          // How much UF volume have we taken so far?
         F32 remUFVol = uFVolume - colUFVol;                                                          // What would remaining UF volume be after subtracting UF volume already taken
         F32 remUFVolCap = RANGE( remUFVol, 0.0F, (F32)MAX_UF_VOLUME_ML );                            // Enforce valid range on remaining UF volume
         F32 uFRate = remUFVolCap / txMinRem;                                                         // What UF rate would be if user selected to adjust it
@@ -1166,7 +1167,9 @@
         {
             rejectReason = REQUEST_REJECT_REASON_INVALID_TREATMENT_STATE;
         }
-        else if ( uFVolume > MAX_UF_VOLUME_ML )
+        // UF volume cannot be set lower than the UF volume that has already been collected
+        else if ( ( uFVolume > MAX_UF_VOLUME_ML ) ||
+                  ( uFVolume <= colUFVol ) )
         {
             rejectReason = REQUEST_REJECT_REASON_UF_VOLUME_OUT_OF_RANGE;
         }