PIC18 ADC measureing issue

void main() {
     PORTE = 0;
     TRISE = 0;
     TRISA = 1;
     PORTA = 0;
     
     k_op = 204;
     k_min = 179;
     k_max = 230;

     v_op = 819;
     v_min = 717;
     v_max = 922;
     
     
     CCP4CON = 10;
     CCPR4H = 0x9C;
     CCPR4L = 0x40;

     CCP4IE_bit = 1;
     CCP4IF_bit = 0;
     GIE_bit = 1;
     PEIE_bit = 1;

     T3CON = 0x41; //Prescaler 1:1, start Timer 1


     ADCON1 = 0x0E;           // Configure AN0 pins as analog
     ADCON0 = 1;              // Configure ADC to work with channel 0 (AN0-RA0)
     delay_ms(1);             // Required for ADC to work properly
     ADCON2 = 0x06;
     CMCON  |= 7;             // Disable comparators
     GO_bit = 1;              // Start convertion
     
     CCP1CON = 0x0C;          // CCP1 configured as PWM (RC2 pin)
     k = 127;
     PWM1_init (1000);
     PWM1_set_duty (k);    // initialize PWM with 80% duty cycle
     PWM1_start();

  
  
     while(1){
     //Do whatever else is required

     v = ADC_Read (0);          // read boost's output voltage

     /////* duty cycle control */////
     
     if ( v >= 819 ) {         // if output voltage >= reference value:
     
        if ( v >= 922 ) {      // if output voltage exceeds max voltge, then:
        
          k = k_max;           // output max duty cycle then,
          k--;                 // decrease duty cycle
          }
     }
     
     if ( v <= 819 ) {         // if output voltage <= reference value:
     
        if ( v <= 717 ) {      // if output voltage is below min voltage, then:
        
          k = k_min;           // output min duty cycle then,
          k++;                 // increase duty cycle
          
          }
     }
     

     
     




     }    // end while loop
}         // end main loop

     if ( v >= 819 ) {         // if output voltage >= reference value:
     
        if ( v >= 922 ) {      // if output voltage exceeds max voltge, then:
        
          k = k_max;           // output max duty cycle then,
          k--;                 // decrease duty cycle
          }
     }
     
     if ( v <= 819 ) {         // if output voltage <= reference value:
     
        if ( v <= 717 ) {      // if output voltage is below min voltage, then:
        
          k = k_min;           // output min duty cycle then,
          k++;                 // increase duty cycle
          
          }
     }

     if ( v >= 819 ) {         // if output voltage >= reference value:
     
        if ( v >= 922 ) {      // if output voltage exceeds max voltge, then:
        
          k = k_max;           // output max duty cycle then,

          }

          k--;                 // decrease duty cycle

     }
     
     if ( v <= 819 ) {         // if output voltage <= reference value:
     
        if ( v <= 717 ) {      // if output voltage is below min voltage, then:
        
          k = k_min;           // output min duty cycle then,

          }

          k++;                 // increase duty cycle
     }

     PWM1_Set_Duty(k); //Assign k to duty cycle