Index: firmware/App/Controllers/Heaters.c
===================================================================
diff -u -r938ebb5c798d4f4a5a7ebf664e7f443f18d2237c -reaeff603027c54d0be5171d519710942672ef623
--- firmware/App/Controllers/Heaters.c	(.../Heaters.c)	(revision 938ebb5c798d4f4a5a7ebf664e7f443f18d2237c)
+++ firmware/App/Controllers/Heaters.c	(.../Heaters.c)	(revision eaeff603027c54d0be5171d519710942672ef623)
@@ -7,8 +7,8 @@
 *
 * @file    Heaters.c
 *
-* @author  (last)      Vinayakam Mani
-* @date    (last)      03-Mar-2026
+* @author  (last)      Michael Garthwaite
+* @date    (last)      30-Mar-2026
 *
 * @author  (original)  Vinayakam Mani
 * @date    (original)  11-Oct-2024
@@ -60,10 +60,8 @@
 #define D5_HEAT_TX_P_COEFFICIENT                                   0.05F                                                           ///< P Term for AC primary heater control during treatment mode.
 #define D5_HEAT_TX_I_COEFFICIENT                                   0.001F                                                          ///< I Term for AC primary heater control during treatment mode.
 
-//#define D45_HEAT_P_COEFFICIENT                                     0.20F                                                           ///< P Term for trimmer heater control.
-//#define D45_HEAT_I_COEFFICIENT                                     0.05F                                                           ///< I Term for trimmer heater control.
-#define D45_HEAT_P_COEFFICIENT                                     0.05F                                                           ///< P Term for trimmer heater control.
-#define D45_HEAT_I_COEFFICIENT                                     0.02F                                                           ///< I Term for trimmer heater control.
+#define D45_HEAT_P_COEFFICIENT                                     0.01F                                                           ///< P Term for trimmer heater control.
+#define D45_HEAT_I_COEFFICIENT                                     0.005F                                                          ///< I Term for trimmer heater control.
 #define D45_HEAT_TX_INIT_FEED_FORWARD                              0.0F                                                            ///< Initial Feed forward term for heater control
 
 #define HEATERS_DATA_PUBLISH_INTERVAL                              ( MS_PER_SECOND / TASK_PRIORITY_INTERVAL )                      ///< Heaters data publish interval.
@@ -84,7 +82,7 @@
 //#define D5_HEAT_CONTROL_INTERVAL_MS                                30000                                                           /// Primary heater control interval in milli seconds
 #define D5_HEAT_CONTROL_INTERVAL_MS                                3000                                                            /// Primary heater control interval in milli seconds
 #define D5_HEAT_CONTROL_INTERVAL_COUNT                             ( D5_HEAT_CONTROL_INTERVAL_MS / TASK_GENERAL_INTERVAL )         ///< Primary heater control interval count.
-#define D45_HEAT_CONTROL_INTERVAL_MS                               ( 1 * MS_PER_SECOND )                                           ///< Trimmer heater control interval in milli seconds
+#define D45_HEAT_CONTROL_INTERVAL_MS                               ( 3 * MS_PER_SECOND )                                           ///< Trimmer heater control interval in milli seconds
 #define D45_HEAT_CONTROL_INTERVAL_COUNT                            ( D45_HEAT_CONTROL_INTERVAL_MS / TASK_GENERAL_INTERVAL )        ///< Trimmer heater control interval count.
 #define D5_TARGET_TEMP_ADJUST_LOW_QD_INTERVAL                      ( 3 * SEC_PER_MIN * MS_PER_SECOND / TASK_GENERAL_INTERVAL )     ///< Adjust primary target temperature - outer loop control interval for low Qd.
 #define D5_TARGET_TEMP_ADJUST_HIGH_QD_INTERVAL                     ( 1 * SEC_PER_MIN * MS_PER_SECOND / TASK_GENERAL_INTERVAL )     ///< Adjust primary target temperature - outer loop control interval for high Qd.
@@ -800,7 +798,7 @@
 
     if ( D5_HEAT == heater )
     {
-        measuredTemperature = getD4AverageTemperature();
+        measuredTemperature = getFilteredTemperatureValue( D4_TEMP );
 
         if ( DD_MODE_HEAT != opMode )
         {
@@ -830,7 +828,7 @@
     }
     else
     {
-        measuredTemperature = getD50AverageTemperature();
+        measuredTemperature = getFilteredTemperatureValue( D50_TEMP );
 
         if ( DD_MODE_HEAT != opMode )
         {
@@ -893,7 +891,7 @@
         if ( D5_HEAT == heater )
         {
             // Inlet temperature post heat exchanger
-            F32 inletTemperature    = getD78AverageTemperature();
+            F32 inletTemperature    = getFilteredTemperatureValue( D78_TEMP );
             F32 deltaTempC          = targetTemperature - inletTemperature;
             F32 capDeltaTempC       = MAX( deltaTempC, HEATERS_ZERO_DELTA_TEMP_C );
             F32 flowrate            = ( getTDDialysateFlowrate() + RINSE_PUMP_EST_FLOWRATE ) / LITER_IN_ML ;
@@ -914,7 +912,7 @@
                targetTemperature = adjustedPrimaryTargetTemp;
             }
 #if 1
-            measuredTemperature = getD4AverageTemperature();
+            measuredTemperature = getFilteredTemperatureValue( D4_TEMP );
             deltaTempC          = fabs( targetTemperature - measuredTemperature );
 
             if ( deltaTempC >= D5_HEATER_DEADBAND_CONTROL )
@@ -923,7 +921,7 @@
                 control[ heater ].data = ctrl;
             }
 #else
-            measuredTemperature = getD4AverageTemperature();
+            measuredTemperature = getFilteredTemperatureValue( D4_TEMP );
             deltaTempC          = targetTemperature - measuredTemperature;
             capDeltaTempC       = fabs(deltaTempC);
             d5_p_gain           = ( D5_HEATER_PWM_ADJ_SLOPE_FACTOR * getTDDialysateFlowrate() ) + D5_HEATER_PWM_INTERCEPT_FACTOR;
@@ -964,7 +962,7 @@
         }
         else
         {
-            measuredTemperature = getD50AverageTemperature();
+            measuredTemperature = getFilteredTemperatureValue( D50_TEMP );
 
             ctrl = runPIController( PI_CONTROLLER_ID_D45_HEAT, targetTemperature, measuredTemperature );
             control[ heater ].data = ctrl;