Index: firmware/App/Controllers/Pressures.c
===================================================================
diff -u -r1efd362566248b63c8293d3ee498017d5b3866bb -r814f249c237f68794350436f11b644b68f5563c8
--- firmware/App/Controllers/Pressures.c	(.../Pressures.c)	(revision 1efd362566248b63c8293d3ee498017d5b3866bb)
+++ firmware/App/Controllers/Pressures.c	(.../Pressures.c)	(revision 814f249c237f68794350436f11b644b68f5563c8)
@@ -41,7 +41,7 @@
 #define PRESSURE_AVERAGE_MULTIPLIER             (1.0 / (F32)PRESSURE_SAMPLES_TO_AVERAGE)        ///< Optimization - multiplying is faster than dividing.
 
 #define PRESSURE_SENSORS_ADC_BITS               12U                                             ///< Pressure sensors ADC bits
-#define PRESSURE_SENSORS_ADC_MAX_COUNT          ( pow(2, PRESSURE_SENSORS_ADC_BITS) )           ///< Pressure sensors max ADC count
+#define PRESSURE_SENSORS_ADC_MAX_COUNT          ( pow(2, PRESSURE_SENSORS_ADC_BITS) - 1 )       ///< Pressure sensors max ADC count
 
 #define MIN_INLET_WATER_PRESSURE                25                                              ///< Minimum water input pressure
 #define INLET_WATER_PRESSURE_PERSISTENCE_COUNT  ( 5 * MS_PER_SECOND / TASK_GENERAL_INTERVAL )   ///< Persistence count for pressure out of range error
@@ -393,7 +393,7 @@
     SELF_TEST_STATUS_T result = SELF_TEST_STATUS_PASSED;
     U16 const inletPressureADCReading = getIntADCReading( INT_ADC_RO_PUMP_INLET_PRESSURE );
 
-    if ( ( inletPressureADCReading <= 0 ) || ( inletPressureADCReading >= PRESSURE_SENSORS_ADC_MAX_COUNT ) )
+    if ( ( inletPressureADCReading == 0 ) || ( inletPressureADCReading >= PRESSURE_SENSORS_ADC_MAX_COUNT ) )
     {
         result = SELF_TEST_STATUS_FAILED;
         SET_ALARM_WITH_1_U32_DATA ( ALARM_ID_PRESSURE_SENSOR_FAULT, inletPressureADCReading );