diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8049f154..e1ff3ead 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,10 +22,18 @@ will consitute of a breaking change warranting a new major release:
 
 - Added parameter to disable STR input for MEKF.
 
+## Changed
+
+- If a primary heater is set to `EXTERNAL CONTROL` and `ON`, the `TCS Controller` will no
+  try to control the temperature of that object.
+- Set lower OP limit of `PLOC` to -5°C.
+
 ## Fixed
 
 - Added prevention of sign jump for target quaternion of GS pointing, which would reduce the
   performance of the controller.
+- Heaters set to `EXTERNAL CONTROL` no longer can be switched off by the `TCS Controller`, if
+  they violate the maximum burn duration of the controller.
 
 # [v7.7.2] 2024-03-06
 
diff --git a/mission/controller/ThermalController.cpp b/mission/controller/ThermalController.cpp
index 2729cec0..c406a5be 100644
--- a/mission/controller/ThermalController.cpp
+++ b/mission/controller/ThermalController.cpp
@@ -1641,7 +1641,11 @@ bool ThermalController::chooseHeater(heater::Switch& switchNr, heater::Switch re
   bool heaterAvailable = true;
 
   HasHealthIF::HealthState mainHealth = heaterHandler.getHealth(switchNr);
+  heater::SwitchState mainState = heaterHandler.getSwitchState(switchNr);
   HasHealthIF::HealthState redHealth = heaterHandler.getHealth(redSwitchNr);
+  if (mainHealth == HasHealthIF::EXTERNAL_CONTROL and mainState == heater::SwitchState::ON) {
+    return false;
+  }
   if (mainHealth != HasHealthIF::HEALTHY) {
     if (redHealth == HasHealthIF::HEALTHY) {
       switchNr = redSwitchNr;
@@ -1656,6 +1660,7 @@ bool ThermalController::chooseHeater(heater::Switch& switchNr, heater::Switch re
   } else {
     ctrlCtx.redSwitchNrInUse = false;
   }
+
   return heaterAvailable;
 }
 
@@ -1792,7 +1797,8 @@ void ThermalController::heaterMaxDurationControl(
   for (unsigned i = 0; i < heater::Switch::NUMBER_OF_SWITCHES; i++) {
     // Right now, we only track the maximum duration for heater which were commanded by the TCS
     // controller.
-    if (currentHeaterStates[i] == heater::SwitchState::ON and
+    if (heaterHandler.getHealth(static_cast<heater::Switch>(i)) != HasHealthIF::EXTERNAL_CONTROL and
+        currentHeaterStates[i] == heater::SwitchState::ON and
         heaterStates[i].trackHeaterMaxBurnTime and
         heaterStates[i].heaterOnMaxBurnTime.hasTimedOut()) {
       heaterStates[i].switchTransition = false;
diff --git a/mission/controller/ThermalController.h b/mission/controller/ThermalController.h
index 1062fe97..6b6d9cde 100644
--- a/mission/controller/ThermalController.h
+++ b/mission/controller/ThermalController.h
@@ -197,9 +197,9 @@ class ThermalController : public ExtendedControllerBase {
   tcsCtrl::TempLimits pcduAcuLimits = tcsCtrl::TempLimits(-35.0, -35.0, 80.0, 85.0, 85.0);
   tcsCtrl::TempLimits pcduPduLimits = tcsCtrl::TempLimits(-35.0, -35.0, 80.0, 85.0, 85.0);
   tcsCtrl::TempLimits plPcduBoardLimits = tcsCtrl::TempLimits(-55.0, -40.0, 80.0, 85.0, 125.0);
-  tcsCtrl::TempLimits plocMissionBoardLimits = tcsCtrl::TempLimits(-30.0, -10.0, 40.0, 45.0, 60);
+  tcsCtrl::TempLimits plocMissionBoardLimits = tcsCtrl::TempLimits(-30.0, -5.0, 40.0, 45.0, 60);
   tcsCtrl::TempLimits plocProcessingBoardLimits =
-      tcsCtrl::TempLimits(-30.0, -10.0, 40.0, 45.0, 60.0);
+      tcsCtrl::TempLimits(-30.0, -5.0, 40.0, 45.0, 60.0);
   tcsCtrl::TempLimits dacLimits = tcsCtrl::TempLimits(-65.0, -40.0, 113.0, 118.0, 150.0);
   tcsCtrl::TempLimits cameraLimits = tcsCtrl::TempLimits(-40.0, -30.0, 60.0, 65.0, 85.0);
   tcsCtrl::TempLimits droLimits = tcsCtrl::TempLimits(-40.0, -30.0, 75.0, 80.0, 90.0);