diff --git a/source/Core/Threads/GUIThread.cpp b/source/Core/Threads/GUIThread.cpp
index cb8ded01..bef78d14 100644
--- a/source/Core/Threads/GUIThread.cpp
+++ b/source/Core/Threads/GUIThread.cpp
@@ -98,7 +98,7 @@ void performCJCC() {
   // Calibrate Cold Junction Compensation directly at boot, before internal components get warm.
   OLED::refresh();
   osDelay(50);
-  if (!isTipDisconnected() && (TipThermoModel::getTipInC() - getHandleTemperature(0) / 10) < 10) {
+  if (!isTipDisconnected() && abs( int(TipThermoModel::getTipInC() - getHandleTemperature(0) / 10)) < 10) {
     uint16_t setoffset = 0;
     // If the thermo-couple at the end of the tip, and the handle are at
     // equilibrium, then the output should be zero, as there is no temperature
@@ -1231,4 +1231,4 @@ void startGUITask(void const *argument) {
       GUIDelay();
     }
   }
-}
\ No newline at end of file
+}