When is following code is dumped into Arduino NANO the output is not as expected after few trials

Question

I'm a beginner of Arduino programming, when I dumped the following code into Arduino NANO board, at the first the output is as expected. But After few trials the 16*2 LCD display is getting off and DC motor pump is running continuously.

      #include <Wire.h>
      #include <Adafruit_MLX90614.h>
      #include <LiquidCrystal_I2C.h>
      LiquidCrystal_I2C lcd(0x27, 16,2);
      
      char *typeName[]={"Object","Ambient"};
      
      Adafruit_MLX90614 mlx = Adafruit_MLX90614();

      const int trigPin = 13;
      const int echoPin = 12;
      #define DCwater_pump 11
   
      long duration;
      int distance;

     void setup() 
     {
          Serial.begin(9600);
          Serial.println("S.O.A.P. DISPENS");

          Serial.print("Ambient = ");
          Serial.print(mlx.readAmbientTempF());
          Serial.print("*F\tObject = ");
          Serial.print(mlx.readObjectTempF());
          Serial.print("*F");
          
                    
          Serial.println();
           
          delay(500);
    

          if (!mlx.begin()) 
          {
              lcd.print("MLX90614 Failed");
              lcd.setCursor(0,1);
              lcd.print("check wiring!");      
              while (1)
              ;
          }  
          Wire.begin();
          lcd.begin(16,2);
          lcd.backlight();  
          lcd.print("S.O.A.P.D. Temp");
          lcd.setCursor(0,1);
          lcd.print("S.O.A.P.D. Temp");          
          delay(500);       
          clearCharacters(2-1,0, 16-1);

          pinMode(trigPin, OUTPUT); 
          pinMode(echoPin, INPUT); 
          pinMode(DCwater_pump, OUTPUT);
       
    }           


void loop() 
{
  
        printTemp('C');
        delay(1000);
        
        printTemp('D');
        delay(1500);

}

float getTemp(char type)
{
  
  float value;
    float tempObjec = mlx.readObjectTempC();
    float tempAmbient = mlx.readAmbientTempC();
   
   if(type =='C')
   {
    value = tempObjec;
   }
   else if(type =='D')
   {
    value = tempAmbient;
   }
   return value;
    
}

            void printTemp(char type)
  {
            clearCharacters(1,0, 16-1 );  
            float TmpC =getTemp(type);
            float TemF;
            TemF = (TmpC*1.8)+32;
            lcd.setCursor(0,1);
            if(type =='C')
            
              {
                lcd.print(typeName[0]); 
                lcd.print(" ");
                lcd.print(TemF);        
                lcd.print((char)223);
                lcd.print("F");      
               }       

                  else if(type =='D')
                  {
                    lcd.print(typeName[1]); 
                    lcd.print(" ");
                    lcd.print(TemF);        
                    lcd.print((char)223);
                    lcd.print("F");        
                  }
  
                  
  }


void clearCharacters(uint8_t row,uint8_t start, uint8_t stop )
{
    for (int i=start; i<=stop; i++)
    {
    lcd.setCursor (i,row);   
    lcd.write(254);
    } 

    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    duration = pulseIn(echoPin, HIGH);
    
    distance= duration*0.034/2;
    
    Serial.print("Distance: "); 
    Serial.println(distance);
    
           if (distance < 30)
          {
           digitalWrite(DCwater_pump,HIGH);
           Serial.println("DC Pump is ON Now!!");
           delay(500);
          }
          else
          {
           digitalWrite(DCwater_pump,LOW);
           Serial.println("DC Pump is OFF Now!!");
           delay(500);
          }

}