Index: firmware/App/Controllers/DrainPump.c
===================================================================
diff -u -rccf1219089b835ab2f9d401c0be0d2000be9010a -r5cee5f88d4d3f18b4178621f1ef175b0873d6248
--- firmware/App/Controllers/DrainPump.c	(.../DrainPump.c)	(revision ccf1219089b835ab2f9d401c0be0d2000be9010a)
+++ firmware/App/Controllers/DrainPump.c	(.../DrainPump.c)	(revision 5cee5f88d4d3f18b4178621f1ef175b0873d6248)
@@ -72,6 +72,8 @@
 
 #define SAFETY_SHUTDOWN_TIMEOUT                MS_PER_SECOND                                                    ///< Drain pump safety shutdown activation timeout.
 
+#define DRAIN_PUMP_OFF_RPM_ADC_COUNT           0xFFFF                                                           ///< ADC count value when pump is off.
+
 /// Enumeration of drain pump states.
 typedef enum DrainPump_States
 {
@@ -249,9 +251,18 @@
  *************************************************************************/
 void execDrainPumpMonitor( void )
 {
-    // Convert speed ADC to RPM
-    currentDrainPumpRPM = CONVERSION_COEFF / getFPGADrainPumpSpeed();
+    U16 const fpgaADCSpeedCount = getFPGADrainPumpSpeed();
 
+    if ( DRAIN_PUMP_OFF_RPM_ADC_COUNT == fpgaADCSpeedCount )
+    {
+        currentDrainPumpRPM = 0;
+    }
+    else
+    {
+        // Convert speed ADC to RPM
+        currentDrainPumpRPM = CONVERSION_COEFF / getFPGADrainPumpSpeed();
+    }
+
     // The RPM is only checked in open loop state that the pump is run at a fixed RPM.
     // The persistent alarm waits for a couple of seconds before raising an alarm, this is supposed to cover
     // when the pump is turned on and it takes a while to ramp up to target RPM.