Index: firmware/App/Controllers/DrainPump.c
===================================================================
diff -u -rccf1219089b835ab2f9d401c0be0d2000be9010a -rab447ebbc380f4c7abc2ae283042a5d0c9e1b9cb
--- firmware/App/Controllers/DrainPump.c	(.../DrainPump.c)	(revision ccf1219089b835ab2f9d401c0be0d2000be9010a)
+++ firmware/App/Controllers/DrainPump.c	(.../DrainPump.c)	(revision ab447ebbc380f4c7abc2ae283042a5d0c9e1b9cb)
@@ -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
 {
@@ -249,13 +251,23 @@
  *************************************************************************/
 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();
+    }
+
+    // TODO this is disabled until RPM is calculated propely.
     // 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.
-    if( drainPumpControlModeSet == PUMP_CONTROL_MODE_OPEN_LOOP )
+    /*if( drainPumpControlModeSet == PUMP_CONTROL_MODE_OPEN_LOOP )
     {
         U32 targetRPM = getTargetDrainPumpRPM();
         F32 threshold = OPEN_LOOP_RPM_OUT_OF_RANGE * targetRPM;
@@ -278,7 +290,7 @@
         {
             activateSafetyShutdown();
         }
-    }
+    }*/
 
     // Publish drain pump data on interval
     publishDrainPumpData();