Index: firmware/App/Controllers/DialOutFlow.c
===================================================================
diff -u -r04334ed8d1e927939718b1d62fb01afef0a2b9a9 -r9d7ad180a18e29ba08bf65228d61b6179ddbfcca
--- firmware/App/Controllers/DialOutFlow.c	(.../DialOutFlow.c)	(revision 04334ed8d1e927939718b1d62fb01afef0a2b9a9)
+++ firmware/App/Controllers/DialOutFlow.c	(.../DialOutFlow.c)	(revision 9d7ad180a18e29ba08bf65228d61b6179ddbfcca)
@@ -49,7 +49,7 @@
 #define MIN_DIAL_OUT_PUMP_PWM_DUTY_CYCLE        0.12            ///< Controller will error if PWM duty cycle < 10%, so set min to 12%.
 
 #define DOP_CONTROL_INTERVAL                    ( 1000 / TASK_GENERAL_INTERVAL ) ///< Interval (ms/task time) at which the dialysate outlet pump is controlled.
-#define DOP_P_COEFFICIENT                       0.0014          ///< P term for dialysate outlet pump control.
+#define DOP_P_COEFFICIENT                       0.0050          ///< P term for dialysate outlet pump control.
 #define DOP_I_COEFFICIENT                       0.0001          ///< I term for dialysate outlet pump control.
 
 #define DOP_MAX_CURR_WHEN_STOPPED_MA            150.0           ///< Motor controller current should not exceed this when pump should be stopped.
@@ -65,10 +65,10 @@
 
 
 /*** setDialOutFlowRxTotalVolumeAndRxTime ***/
-#define DOP_REV_PER_LITER                       124.0           ///< Rotor revolutions per liter.
+#define DOP_REV_PER_LITER                       150.24          ///< Rotor revolutions per liter.
 #define DOP_ML_PER_MIN_TO_PUMP_RPM_FACTOR       ( DOP_REV_PER_LITER / ML_PER_LITER )   ///< Conversion factor from mL/min to pump motor RPM.
 #define DOP_GEAR_RATIO                          32.0            ///< Pump motor to pump gear ratio.
-#define DOP_MOTOR_RPM_TO_PWM_DC_FACTOR          0.00042         ///< ~24 DPo motor RPM = 1% PWM duty cycle.
+#define DOP_MOTOR_RPM_TO_PWM_DC_FACTOR          0.00035         ///< ~28 DPo motor RPM = 1% PWM duty cycle.
 #define DOP_PWM_ZERO_OFFSET                     0.1             ///< 10% PWM duty cycle = zero speed.
 #define DOP_PWM_FROM_ML_PER_MIN(rate)           ( (rate) * DOP_ML_PER_MIN_TO_PUMP_RPM_FACTOR * DOP_GEAR_RATIO * DOP_MOTOR_RPM_TO_PWM_DC_FACTOR + DOP_PWM_ZERO_OFFSET )  ///< Macro converts a flow rate to an estimated PWM duty cycle %.
 
@@ -521,8 +521,17 @@
             F32 refVol = getTotalTargetDialOutUFVolumeInMl();
             F32 totVol = getTotalMeasuredUFVolumeInMl();
             F32 newPWM;
+            F32 deltaPWM;
 
+            // get new PWM from PI controller
             newPWM = runPIController( PI_CONTROLLER_ID_ULTRAFILTRATION, refVol, totVol );
+            // limit PWM change to max
+            deltaPWM = newPWM - dialOutPumpPWMDutyCyclePctSet;
+            if ( FABS( deltaPWM ) > MAX_DIAL_OUT_PUMP_PWM_STEP_CHANGE )
+            {
+                newPWM = ( deltaPWM < 0.0 ? dialOutPumpPWMDutyCyclePctSet - MAX_DIAL_OUT_PUMP_PWM_STEP_CHANGE : dialOutPumpPWMDutyCyclePctSet + MAX_DIAL_OUT_PUMP_PWM_STEP_CHANGE );
+            }
+            // set new PWM
             dialOutPumpPWMDutyCyclePctSet = newPWM;
             setDialOutPumpControlSignalPWM( newPWM );
         }