Index: firmware/App/Services/SystemComm.c
===================================================================
diff -u -r46bf7baaa9d8095e0405b018fcd4bc594907797e -red02e43964af252e4adf0b0ca7a2975a5d9d4a72
--- firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 46bf7baaa9d8095e0405b018fcd4bc594907797e)
+++ firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision ed02e43964af252e4adf0b0ca7a2975a5d9d4a72)
@@ -888,6 +888,10 @@
             handleDGScheduledRunsRequest( message );
             break;
 
+        case MSG_ID_HD_REQUEST_DG_SERVICE_MODE:
+            handleServiceModeRequest( message );
+            break;
+
         // NOTE: This case must be last
         case MSG_ID_DG_TESTER_LOGIN_REQUEST:
             handleTesterLogInRequest( message );
@@ -1129,11 +1133,11 @@
                 break;
 
             case MSG_ID_FILTER_FLUSH_TIME_PERIOD_OVERRIDE:
-                handleFilterFlushTimePeriodOverride( message );
+                handleFilterFlushTimePeriodOverride(message);
                 break;
 
-            case MSG_ID_DG_FANS_RPM_OVERRIDE:
-                handleFansRPMOverride( message );
+            case MSG_ID_DG_BLOCK_MESSAGE_TRANSMISSION:
+                handleTestBlockMessagesRequest( message );
                 break;
 
             case MSG_ID_DG_STOP_RTC_CLOCK:
@@ -1144,10 +1148,6 @@
                 handleSetDrainPumpMeasuredRPMOverrideRequest( message );
                 break;
 
-            case MSG_ID_DG_BLOCK_MESSAGE_TRANSMISSION:
-                handleTestBlockMessagesRequest( message );
-                break;
-
             case MSG_ID_DG_SUPER_CLEAR_ALARMS_CMD:
                 handleTestSuperClearAlarmsRequest( message );
                 break;
@@ -1160,6 +1160,10 @@
                 handleTestFansRPMAlarmStartTimeOffsetRequest( message );
                 break;
 
+            case MSG_ID_DG_FANS_RPM_OVERRIDE:
+                handleFansRPMOverride( message );
+                break;
+
             case MSG_ID_DG_USED_ACID_VOLUME_ML_OVERRIDE:
                 handleTestUsedAcidVolumeMLOverrideRequest( message );
                 break;
@@ -1192,6 +1196,14 @@
                 handleSetDGUsageInfoRecord( message );
                 break;
 
+            case MSG_ID_DG_SET_OP_MODE_REQUEST:
+                handleTestSetOpModeRequest( message );
+                break;
+
+            case MSG_ID_DG_RESERVOIR_TARE_REQUEST:
+                handleTestTareReservoirRequest( message );
+                break;
+
             case MSG_ID_HD_REQUEST_DG_ALARMS:
                 handleResendAllAlarmsCommand( message );
                 break;
Index: firmware/App/Services/SystemCommMessages.c
===================================================================
diff -u -r46bf7baaa9d8095e0405b018fcd4bc594907797e -red02e43964af252e4adf0b0ca7a2975a5d9d4a72
--- firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 46bf7baaa9d8095e0405b018fcd4bc594907797e)
+++ firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision ed02e43964af252e4adf0b0ca7a2975a5d9d4a72)
@@ -23,7 +23,6 @@
 #include "Compatible.h"
 #include "ConcentratePumps.h"
 #include "ConductivitySensors.h"
-#include "Fans.h"
 #include "FPGA.h"
 #include "Heaters.h"
 #include "ModeFill.h"
@@ -368,7 +367,6 @@
     return result;
 }
 
-
 // ***********************************************************************
 // **************** Message Handling Helper Functions ********************
 // ***********************************************************************
@@ -1392,6 +1390,56 @@
 
 /*********************************************************************//**
  * @brief
+ * The handleTestSetOpModeRequest function handles a request to set the
+ * DG operation mode.
+ * @details Inputs: none
+ * @details Outputs: message handled
+ * @param message a pointer to the message to handle
+ * @return none
+ *************************************************************************/
+void handleTestSetOpModeRequest( MESSAGE_T *message )
+{
+    BOOL result = FALSE;
+
+    if ( message->hdr.payloadLen == sizeof(U32) )
+    {
+        U32 mode;
+
+        memcpy( &mode, message->payload, sizeof(U32) );
+        result = testSetOperationMode( (DG_OP_MODE_T)mode );
+    }
+
+    // Respond to request
+    sendTestAckResponseMsg( (MSG_ID_T)message->hdr.msgID, result );
+}
+
+/*********************************************************************//**
+ * @brief
+ * The handleTestTareReservoirRequest function handles a request to tare a
+ * given reservoir's weight.
+ * @details Inputs: none
+ * @details Outputs: message handled
+ * @param message a pointer to the message to handle
+ * @return none
+ *************************************************************************/
+void handleTestTareReservoirRequest( MESSAGE_T *message )
+{
+    BOOL result = FALSE;
+
+    if ( message->hdr.payloadLen == sizeof(U32) )
+    {
+        U32 res;
+
+        memcpy( &res, message->payload, sizeof(U32) );
+        result = testTareReservoir( res );
+    }
+
+    // Respond to request
+    sendTestAckResponseMsg( (MSG_ID_T)message->hdr.msgID, result );
+}
+
+/*********************************************************************//**
+ * @brief
  * The handleSetHDOperationMode function receives the HD operation modes data
  * publish message.
  * @details Inputs: none
@@ -3181,37 +3229,6 @@
 }
 
 /*********************************************************************//**
- * @brief
- * The handleFansRPMOverride function handles a request to override a fans RPM value.
- * @details Inputs: none
- * @details Outputs: message handled
- * @param message a pointer to the message to handle
- * @return none
- *************************************************************************/
-void handleFansRPMOverride( MESSAGE_T *message )
-{
-    TEST_OVERRIDE_ARRAY_PAYLOAD_T payload;
-    BOOL result = FALSE;
-
-    // verify payload length
-    if ( sizeof(TEST_OVERRIDE_ARRAY_PAYLOAD_T) == message->hdr.payloadLen )
-    {
-        memcpy( &payload, message->payload, sizeof(TEST_OVERRIDE_ARRAY_PAYLOAD_T) );
-        if ( FALSE == payload.reset )
-        {
-            result = testSetFanRPMOverride( payload.index, payload.state.f32 );
-        }
-        else
-        {
-            result = testResetFanRPMOverride( payload.index );
-        }
-    }
-
-    // respond to request
-    sendTestAckResponseMsg( (MSG_ID_T)message->hdr.msgID, result );
-}
-
-/*********************************************************************//**
 * @brief
 * The handleStopDGRTCClock function handles a request to stop the RTC clock.
 * @details Inputs: none
@@ -3350,10 +3367,41 @@
 
 /*********************************************************************//**
  * @brief
- * The handleTestFansRPMAlarmStartTimeOffsetRequest function handles a
- * request to set the fans RPM alarm start time offset.
+ * The handleFansRPMOverride function handles a request to override a fans RPM value.
  * @details Inputs: none
  * @details Outputs: message handled
+ * @param message a pointer to the message to handle
+ * @return none
+ *************************************************************************/
+void handleFansRPMOverride( MESSAGE_T *message )
+{
+    TEST_OVERRIDE_ARRAY_PAYLOAD_T payload;
+    BOOL result = FALSE;
+
+    // verify payload length
+    if ( sizeof(TEST_OVERRIDE_ARRAY_PAYLOAD_T) == message->hdr.payloadLen )
+    {
+        memcpy( &payload, message->payload, sizeof(TEST_OVERRIDE_ARRAY_PAYLOAD_T) );
+        if ( FALSE == payload.reset )
+        {
+            result = testSetFanRPMOverride( payload.index, payload.state.f32 );
+        }
+        else
+        {
+            result = testResetFanRPMOverride( payload.index );
+        }
+    }
+
+    // respond to request
+    sendTestAckResponseMsg( (MSG_ID_T)message->hdr.msgID, result );
+}
+
+/*********************************************************************//**
+ * @brief
+ * The handleTestFansRPMAlarmStartTimeOverrideRequest function handles a
+ * request to override the fan RPM alarm start time.
+ * @details Inputs: none
+ * @details Outputs: message handled
  * @param message : a pointer to the message to handle
  * @return none
  *************************************************************************/
@@ -3376,7 +3424,6 @@
 }
 
 /*********************************************************************//**
- * @brief
  * The handleTestUsedAcidVolumeMLOverrideRequest function handles a
  * request to override the acid volume.
  * @details Inputs: none
@@ -3669,13 +3716,80 @@
 
 /*********************************************************************//**
 * @brief
-* The handleResendAllAlarmsCommand function handles a request to re-send
-* all active DG alarms.
+* The handleServiceModeRequest function handles a request to enter service
+* mode.
 * @details Inputs: none
 * @details Outputs: message handled
 * @param message a pointer to the message to handle
 * @return none
 *************************************************************************/
+void handleServiceModeRequest( MESSAGE_T *message )
+{
+    BOOL status = FALSE;
+    DG_OP_MODE_T currentMode = getCurrentOperationMode();
+    REQUEST_REJECT_REASON_CODE_T reject;
+
+    if ( 0 == message->hdr.payloadLen )
+    {
+        if ( ( DG_MODE_STAN == currentMode ) || ( DG_MODE_FAUL == currentMode ) )
+        {
+            status = TRUE;
+            requestNewOperationMode( DG_MODE_SERV );
+            reject = REQUEST_REJECT_REASON_NONE;
+        }
+        else
+        {
+            reject = REQUEST_REJECT_REASON_DG_NOT_IN_STANDBY_IDLE_STATE;
+        }
+    }
+    else
+    {
+        reject = REQUEST_REJECT_REASON_INVALID_REQUEST_FORMAT;
+    }
+
+    // Respond to request
+    sendTestAckResponseMsg( (MSG_ID_T)message->hdr.msgID, status );
+    sendServiceModeResponse( status, (U32)reject );
+}
+
+/*********************************************************************//**
+ * @brief
+ * The sendServiceModeResponse function sends out the DG response to a
+ * UI request to go to service mode.
+ * @details Inputs: none
+ * @details Outputs: Service mode request response msg constructed and queued
+ * @param accepted TRUE if request was accepted, FALSE if not
+ * @param rejCode Reject reason code explaining why request was rejected
+ * @return none
+ *************************************************************************/
+void sendServiceModeResponse( BOOL accepted, U32 rejCode )
+{
+    MESSAGE_T msg;
+    U08 *payloadPtr = msg.payload;
+
+    // Create a message record
+    blankMessage( &msg );
+    msg.hdr.msgID = MSG_ID_DG_RESPONSE_SERVICE_MODE_REQUEST;
+    msg.hdr.payloadLen = sizeof( BOOL ) + sizeof( U32 );
+
+    memcpy( payloadPtr, &accepted, sizeof( BOOL ) );
+    payloadPtr += sizeof( BOOL );
+    memcpy( payloadPtr, &rejCode, sizeof( U32 ) );
+
+    // Serialize the message (w/ sync, CRC, and appropriate CAN padding) and add serialized message data to appropriate comm buffer
+    serializeMessage( msg, COMM_BUFFER_OUT_CAN_DG_2_HD, ACK_REQUIRED );
+}
+
+/*********************************************************************//**
+ * @brief
+ * The sendUIServiceModeResponse function sends out the DG response to a
+ * UI request to go to service mode.
+ * @details Inputs: none
+ * @details Outputs: Service mode request response msg constructed and queued
+ * @param accepted TRUE if request was accepted, FALSE if not
+ * @param rejCode Reject reason code explaining why request was rejected
+ * @return none
+ *************************************************************************/
 void handleResendAllAlarmsCommand( MESSAGE_T *message )
 {
     BOOL result = FALSE;
Index: firmware/App/Services/SystemCommMessages.h
===================================================================
diff -u -r46bf7baaa9d8095e0405b018fcd4bc594907797e -red02e43964af252e4adf0b0ca7a2975a5d9d4a72
--- firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision 46bf7baaa9d8095e0405b018fcd4bc594907797e)
+++ firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision ed02e43964af252e4adf0b0ca7a2975a5d9d4a72)
@@ -155,6 +155,12 @@
 // MSG_ID_DG_SCHEDULED_RUNS_INFO
 void handleDGScheduledRunsRequest( MESSAGE_T *message );
 
+// MSG_ID_UI_REQUEST_SERVICE_MODE
+void handleServiceModeRequest( MESSAGE_T *message );
+
+// MSG_ID_DG_RESPONSE_SERVICE_MODE_REQUEST
+void sendServiceModeResponse( BOOL accepted, U32 rejCode );
+
 // MSG_ID_HD_OP_MODE
 BOOL handleSetHDOperationMode( MESSAGE_T *message );
 
@@ -365,6 +371,12 @@
 // MSG_ID_DG_DRAIN_PUMP_MEASURED_RPM_OVERRIDE
 void handleSetDrainPumpMeasuredRPMOverrideRequest( MESSAGE_T *message );
 
+// MSG_ID_DG_ALARM_INFO_SEND_INTERVAL_OVERRIDE
+void handleTestAlarmInfoSendIntervalOverrideRequest( MESSAGE_T *message );
+
+// MSG_ID_DG_SUPER_CLEAR_ALARMS_CMD
+void handleTestSuperClearAlarmsRequest( MESSAGE_T *message );
+
 // MSG_ID_DG_SET_FANS_RPM_ALARM_START_TIME_OFFSET
 void handleTestFansRPMAlarmStartTimeOffsetRequest( MESSAGE_T *message );
 
@@ -386,12 +398,27 @@
 // MSG_ID_DG_HD_COMMUNICATION_STATUS
 void handleTestHDCommunicationStatusOverrideRequest(MESSAGE_T *message);
 
+// MSG_ID_DG_USED_ACID_VOLUME_ML_OVERRIDE
+void handleTestUsedAcidVolumeMLOverrideRequest(MESSAGE_T *message);
+
+// MSG_ID_DG_USED_BICARB_VOLUME_ML_OVERRIDE
+void handleTestUsedBicarbVolumeMLOverrideRequest(MESSAGE_T *message);
+
 // MSG_ID_DG_GET_USAGE_INFO_RECORD
 void handleGetDGUsageInfoRecord( MESSAGE_T *message );
 
 // MSG_ID_DG_SET_USAGE_INFO_RECORD
 void handleSetDGUsageInfoRecord( MESSAGE_T *message );
 
+// MSG_ID_DG_SET_OP_MODE_REQUEST
+void handleTestSetOpModeRequest( MESSAGE_T *message );
+
+// MSG_ID_DG_RESERVOIR_TARE_REQUEST
+void handleTestTareReservoirRequest( MESSAGE_T *message );
+
+// MSG_ID_HD_OP_MODE
+BOOL handleSetHDOperationMode( MESSAGE_T *message );
+
 // MSG_ID_HD_REQUEST_DG_ALARMS
 void handleResendAllAlarmsCommand( MESSAGE_T *message );