Designing a General Purpose Heat Pump Controller

[hydronics]

Hi all,

I have not investigated this device fully but I really like the look of it. It takes the 3 year old Arduino Deumilanove architecture and puts some nice inputs/outputs for HVAC applications:

- 8 relay outputs 10 A, 250 VAC
- 4 Opto-isolated inputs 5 to 30 VDC
- 3 Analog inputs (10 bit), jumper selectable for 0 to 5 VDC or 0 to 20 mA

I can't post a URL but it is a sparkfun product #9526 relay I/O board

[buffalobillpatrick]

A/C suggested that I post this:

/********************************************************
 *
 * ARDUINO MASTER HEAT SYSTEM Controller.
 *
 * 3 Heat sources: Solar, Heat Pump (HP), & Boiler, 
 * Heats 2 Load tanks: DHW & Buffer (BT).
 *
 * The priority of Heat Source used is: Solar, Heat Pump, Boiler
 * so as to minimize cost.
 *
 * DHW has prority over BT
 * The DHW Tank temperature is maintained within limits set by 2 pots.
 *
 * If Winter SW is on, the BT temperature is maintained within limits 
 * set by Outdoor Reset (ODR) calculation to minimize BT temperature.
 *
 * The DHW_HP section can be skipped with DHW HP SKIP Switch on.
 * The Solar_HP section can be skipped with Solar HP SKIP Switch on.
 *
 * If Solar is not raising Load temp. then code Downshifts to using HP.
 * If HP is not raising Load temp. then code Downshifts to using Boiler.
 *
 *
 * INPUTS:
 *
 * Winter switch                 //control switches
 * DHW HP SKIP switch
 * SOLAR HP SKIP switch
 *
 * HP ALIVE Signal from HP Slave
 * 
 * BUFFER_tank_lo_pot            //control pots   
 * BUFFER_tank_hi_pot
 * BUFFER_Delta_pot
 * DHW_Delta_pot        
 * DHW_target_pot        
 * Solar_lo_pot        
 * Solar_med_pot        
 * Solar_hi_pot
 * 
 * OUTDOOR_sensor               //10K NTC Thermisters
 * BUFFER_tank_sensor 
 * SOLAR_tank_sensor                     
 * DHW_tank_sensor        
 *
 * MQ-2_GAS_sensor                            
 *
 *
 * OUTPUTS:
 *
 * LCD Display: Status & Progression through code
 *
 * BO_HEAT_CALL_RLY_R1     Boiler heat call Relay 1
 * DHW_P2_RLY_R2           DHW Pump Relay 2
 * BT_P3_RLY_R3            Buffer tank Pump Relay 3
 * SOLAR_P4_RLY_R4         Solar tank Pump Relay 4
 * HP_HEAT_CALL_RLY_R5     Heat Pump call Relay 5, 
 *                                         Powers on Slave HP Arduino
 *
 *
 ********************************************************/


#include <Wire.h>
#include <LCD.h>
#include <LiquidCrystal_I2C.h>


#define I2C_ADDR    0x3F // <<----- Add your address here.  Find it from I2C Scanner

#define BACKLIGHT_PIN     3  //define LCD digital pins
#define En_pin  2
#define Rw_pin  1             //can't use 0 & 1 Tx Rx
#define Rs_pin  0
#define D4_pin  4
#define D5_pin  5              //can use 2 -> 12 below in code
#define D6_pin  6
#define D7_pin  7

LiquidCrystal_I2C lcd(I2C_ADDR,En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin);

#define SDA                   A4  //RESERVE I2C for LCD           
#define SCL                   A5  


#define mux_analog_in         A0  // multiplexer to Arduino analog in pin A0

#define WINTER_SW             15  //A1, D15  Winter sw
#define DHW_HP_SKIP_SW        16  //A2. D16  DHW HP SKIP sw
#define SOLAR_HP_SKIP_SW      17  //A3, D17  SOLAR HP SKIP sw

                              // D0 = RX, D1 = TX, reserved
                                     // digital output pin relay control
                                     
#define  BO_HEAT_CALL_RLY_R1     2   // Boiler heat call Relay    Songle 10A
#define  DHW_P2_RLY_R2           3   // DHW Pump2 Relay           D1202  2.5A
#define  BT_P3_RLY_R3            4   // Buffer tank Pump3 Relay   D1202  2.5A

                                     //Split R1 & R5 into seperate groups
                                     //as songle relay coil = 90ma
                                     //each group can source 150 mA. max
                                     //group 1 ends with D4
                                     //group 2 starts with D5
                                     
#define  SOLAR_P4_RLY_R4         5   // Solar tank Pump4 Relay   D1202  2.5A
#define  HP_HEAT_CALL_RLY_R5     6   // Heat Pump call Relay     Songle 10A

       
                                 //define digital output pins for MUX
                                 // multiplexer address select lines (A/B/C/D)
const byte mux_address_A       = 7;
const byte mux_address_B       = 8; 
const byte mux_address_C       = 9; 
const byte mux_address_D       = 10; 
const byte mux_enable          = 13;  // multiplexer enable


#define ALARM                   11  // D11 PWM OUTPUT to Audible Alarm

#define HP_ALIVE                12  // D12 input from SLAVE Arduino, HP ALIVE R1


#define BUFFER_tank_lo_pot     0    //analog signals into MUX          
#define BUFFER_tank_hi_pot     1    // these are not analog pins on Arduino
#define BUFFER_Delta_pot       2

#define DHW_Delta_pot          3
#define DHW_target_pot         4

#define Solar_lo_pot           5
#define Solar_med_pot          6
#define Solar_hi_pot           7                                


#define OUTDOOR_sensor         8     //analog signals into MUX 
#define BUFFER_tank_sensor     9     // these are not analog pins on Arduino
#define SOLAR_tank_sensor      10               
#define DHW_tank_sensor        11 

//#define HP_Source_IN_sensor    12                
//#define HP_Source_OUT_sensor   13                
//#define HP_Load_IN_sensor      14

#define MQ2_GAS_sensor         15

#define GAS_LIMIT              30

//Out Door Reset parameters
#define OUTDOOR_hi_control_temp  60.0  //House don't require heat
#define OUTDOOR_lo_control_temp -20.0  //Minimum expected OD temp

float OUTDOOR_range;
float BUFFER_tank_range;
float ODR_ratio;

                                 // 8 POTS must be adjusted with testing
int Solar_lo_cntl_temp_pot;      // These are read & stored in Sertup code   
int Solar_med_cntl_temp_pot;       
int Solar_hi_cntl_temp_pot;                                         
int DHW_tank_target_temp_pot;  
int BUFFER_tank_hi_limit_pot;  
int BUFFER_tank_lo_limit_pot;  
int DHW_delta_pot;          
int BUFFER_delta_pot;        

int OUTDOOR_temp;  
int SOLAR_tank_temp;
int DHW_tank_temp;

int BUFFER_tank_temp;
int BUFFER_tank_target_temp;  


//int HP_Source_IN_temp;                  
//int HP_Source_OUT_temp;               
//int HP_Load_IN_temp;                        
//int HP_Load_OUT_temp;        

unsigned long T1;
unsigned long T2;
unsigned long TT;

int I;

int START_T;
int NOW_T;


int sensor_data;
 

boolean WINTER_SW_BOOL          = false;
boolean DHW_HP_SKIP_BOOL        = false;
boolean SOLAR_HP_SKIP_BOOL      = false;
boolean DHW_DOWNSHIFT_BOOL1     = false;
boolean DHW_DOWNSHIFT_BOOL2     = false;
boolean BT_DOWNSHIFT_BOOL1      = false;
boolean BT_DOWNSHIFT_BOOL2      = false;

 
void setup(void) 
  {  
  pinMode (mux_analog_in, INPUT);  //MUX DATA INPUT
  pinMode (mux_address_A, OUTPUT); // multiplexer address select lines (A/B/C/D)
  pinMode (mux_address_B, OUTPUT); 
  pinMode (mux_address_C, OUTPUT); 
  pinMode (mux_address_D, OUTPUT); 
  pinMode (mux_enable,    OUTPUT); // multiplexer enable
  
  pinMode (ALARM,         OUTPUT); // Audible Alarm

  
  pinMode(BO_HEAT_CALL_RLY_R1,        OUTPUT); //digital output to relays
  pinMode(DHW_P2_RLY_R2,              OUTPUT); //digital output to relays
  pinMode(BT_P3_RLY_R3,               OUTPUT); //digital output to relays
  pinMode(SOLAR_P4_RLY_R4,            OUTPUT); //digital output to relays
  pinMode(HP_HEAT_CALL_RLY_R5,        OUTPUT); //digital output to relays 
  
  pinMode(WINTER_SW,                   INPUT); //Winter switch   
  pinMode(DHW_HP_SKIP_SW,              INPUT); //DHW HP SKIP switch   
  pinMode(SOLAR_HP_SKIP_SW,            INPUT); //SOLAR HP SKIP switch 
  pinMode(HP_ALIVE,                    INPUT); //HP ALIVE 
  
  digitalWrite (BO_HEAT_CALL_RLY_R1,        HIGH); //OFF
  digitalWrite (DHW_P2_RLY_R2,              HIGH); //OFF
  digitalWrite (BT_P3_RLY_R3,               HIGH); //OFF
  digitalWrite (SOLAR_P4_RLY_R4,            HIGH); //OFF
  digitalWrite (HP_HEAT_CALL_RLY_R5,        HIGH); //OFF
  
  digitalWrite (ALARM,                      HIGH); //OFF

  
//  Serial.begin(9600); // start serial communication

//  custom_delay_5sec();        //Delay 5 sec. & Check for GAS      //time to enable monitor window

[buffalobillpatrick]

Setup Code:

  
//  Serial.println(F("........Hello world!......."));
//  delay(100); 
  
  lcd.begin (16,2); //  <<----- My LCD is 16x2
  lcd.clear();
 
  //Switch on the backlight
  lcd.setBacklightPin(BACKLIGHT_PIN,POSITIVE);
  lcd.setBacklight(HIGH);  


  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("BBP HEAT SYSTEM"));
  lcd.setCursor(0,1);
  lcd.print(F("MASTER CONTROLER"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          

  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("START SETUP"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                           
         
 
  if (digitalRead(WINTER_SW) == HIGH)
  {
  WINTER_SW_BOOL = true;
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("WINTER SW = ON"));
  lcd.setCursor(0,1);
  lcd.print(F("KEEP BT HOT !!!!"));  
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                           
  }
  else
  {
  WINTER_SW_BOOL = false; 
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("WINTER SW = OFF"));
  lcd.setCursor(0,1);  //clear 2nd line
  lcd.print(F("BT IS NOT USED"));    
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          
  }    
 
  if (digitalRead(DHW_HP_SKIP_SW) == HIGH)
  {
  DHW_HP_SKIP_BOOL = true;
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("DHW_HP_SKIP = ON")); 
  lcd.setCursor(0,1);
  lcd.print(F("HP DONT HEAT DHW"));    
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                           
  }
  else
  {
  DHW_HP_SKIP_BOOL = false; 
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("DHW_HP_SKIP= OFF"));    
  lcd.setCursor(0,1);
  lcd.print(F("HP MAY HEAT DHW"));    
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          
  }  
 
  if (digitalRead(SOLAR_HP_SKIP_SW) == HIGH)
  {
  SOLAR_HP_SKIP_BOOL = true;
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("SOL_HP_SKIP=ON")); 
  lcd.setCursor(0,1);
  lcd.print(F("SOL&HP SKIPED"));    
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                           
  }
  else
  {
  SOLAR_HP_SKIP_BOOL = false; 
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("SOL_HP_SKIP=OFF")); 
  lcd.setCursor(0,1);
  lcd.print(F("SOL&HP ENABLED"));     
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                           
  }


    
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("Read 8 Cntl Pots")); 
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          


                   //read the 8 control pots
  BUFFER_tank_hi_limit_pot =    (readSensor_F (BUFFER_tank_hi_pot));
  
  //BUFFER_tank_hi_limit_pot = 130;  //debug
  
  BUFFER_tank_lo_limit_pot =    (readSensor_F (BUFFER_tank_lo_pot));
  
  //BUFFER_tank_lo_limit_pot = 85;  //debug
  
  BUFFER_delta_pot        =    ((readSensor_F (BUFFER_Delta_pot)) / 10);
  
  //BUFFER_delta_pot           =  5;  //debug

  DHW_delta_pot           =    ((readSensor_F (DHW_Delta_pot)) / 10);

  //DHW_delta_pot           =  4;  //debug

  Solar_lo_cntl_temp_pot    =    (readSensor_F (Solar_lo_pot));
  
  //Solar_lo_cntl_temp_pot    = 39;   //debug
 
  Solar_med_cntl_temp_pot    =    (readSensor_F (Solar_med_pot));
  
  // Solar_med_cntl_temp_pot    = 85;   //debug
  
  Solar_hi_cntl_temp_pot    =    (readSensor_F (Solar_hi_pot));
    
  //Solar_hi_cntl_temp_pot    = 149;   //debug

  DHW_tank_target_temp_pot  =    (readSensor_F (DHW_target_pot));; 

  //DHW_tank_target_temp_pot  =  138;  //debug
 
 
  lcd.clear();  
  lcd.home (); // go home
  lcd.print(F("BT Hi Pot = "));
  lcd.print(BUFFER_tank_hi_limit_pot);
  lcd.setCursor(0,1);  
  lcd.print(F("BT Lo Pot = "));
  lcd.print(BUFFER_tank_lo_limit_pot);
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          

  
  lcd.clear();  
  lcd.home (); // go home
  lcd.print(F("BT Delta Pot ="));
  lcd.print(BUFFER_delta_pot);
  lcd.setCursor(0,1);  
  lcd.print(F("DHW Delta Pot="));
  lcd.print(DHW_delta_pot);
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          


  lcd.clear();  
  lcd.home (); // go home
  lcd.print(F("Solar Lo Pot="));
  lcd.print(Solar_lo_cntl_temp_pot);
  lcd.setCursor(0,1);  
  lcd.print(F("Solar MedPot="));
  lcd.print(Solar_med_cntl_temp_pot);
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          

  
  lcd.clear();  
  lcd.home (); // go home
  lcd.print(F("Solar HiPot="));
  lcd.print(Solar_hi_cntl_temp_pot);
  lcd.setCursor(0,1);  
  lcd.print(F("DHW Tgt Pot="));
  lcd.print(DHW_tank_target_temp_pot);
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          



  OUTDOOR_temp         =  (readSensor_F (OUTDOOR_sensor));
  BUFFER_tank_temp     =  (readSensor_F (BUFFER_tank_sensor));
  lcd.clear();  
  lcd.home (); // go home
  lcd.print(F("OD Temp = ")); 
  lcd.print(OUTDOOR_temp);
  lcd.setCursor(0,1);  
  lcd.print(F("BT Temp = ")); 
  lcd.print(BUFFER_tank_temp);
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                             

    
  SOLAR_tank_temp      =  (readSensor_F (SOLAR_tank_sensor));
  DHW_tank_temp        =  (readSensor_F (DHW_tank_sensor));
  lcd.clear();  
  lcd.home (); // go home
  lcd.print(F("SOLAR Temp = ")); 
  lcd.print(SOLAR_tank_temp);
  lcd.setCursor(0,1);  
  lcd.print(F("DHW Temp = ")); 
  lcd.print(DHW_tank_temp);
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          
    



  if (WINTER_SW_BOOL == true) //Run this section if Winter Sw is ON
  { 
    
  OUTDOOR_range = ( OUTDOOR_hi_control_temp - OUTDOOR_lo_control_temp );
  
  BUFFER_tank_range = ( BUFFER_tank_hi_limit_pot - BUFFER_tank_lo_limit_pot );
 
  ODR_ratio = ( BUFFER_tank_range / OUTDOOR_range );
  
  lcd.clear();  
  lcd.home (); // go home
  lcd.print(F("ODR Ratio = "));
  lcd.print(ODR_ratio);
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          

  lcd.clear();  
  lcd.home (); // go home
  lcd.print(F("ODR Ratio Means:"));
  lcd.setCursor(0,1);  
  lcd.print(F("IF OD Temp Drops"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          
  
  lcd.clear();  
  lcd.home (); // go home
  lcd.print(F("By 1 *F, Then"));
  lcd.setCursor(0,1);  
  lcd.print(F("BT Tgt Goes Up"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          
  lcd.clear();  
  lcd.home (); // go home
  lcd.print(F("By "));
  lcd.print(ODR_ratio);
  lcd.print(F(" *F"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          

  }  //end Winter Sw = true  


  
  lcd.clear();  
  lcd.home (); // go home 
  lcd.print(F("END SETUP"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          

  }    //end setup

[buffalobillpatrick]

Main Loop part 1

  
void loop ()
{

  //DHW has 1st priority
  DHW_CODE:

  DHW_tank_temp   =  (readSensor_F (DHW_tank_sensor));
  
  DHW_tank_temp = 130;  //debug 
  
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("DHW TANK = "));
  lcd.print(DHW_tank_temp);
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
                          

  
  //Test if DHW needs to start heating
  if ( DHW_tank_temp < ( DHW_tank_target_temp_pot - DHW_delta_pot )) 
  {
  
  do  //while DHW_tank_temp < DHW_tank_target_temp_pot
  {
    
  lcd.clear();
  lcd.home (); // go home 
  lcd.print(F("DHW NEEDS HEAT"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS  



  if (SOLAR_HP_SKIP_BOOL == false)
  {                              //Run this section if SOLAR HP SKIP = OFF
     

  SOLAR_tank_temp = (readSensor_F (SOLAR_tank_sensor));
  
  SOLAR_tank_temp = 150;  //debug
   
  lcd.clear();
  lcd.home (); // go home 
  lcd.print(F("Solar Tank = "));
  lcd.print(SOLAR_tank_temp);
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 


  //Is Solar Hot enough for Solar -> DHW Direct
  //AND Is Downshift Bool1 false  
  if (( SOLAR_tank_temp >= Solar_hi_cntl_temp_pot )
     && 
     ( DHW_DOWNSHIFT_BOOL1 == false ))
  {
  digitalWrite (BO_HEAT_CALL_RLY_R1,  HIGH);
  digitalWrite (DHW_P2_RLY_R2,        LOW);  //ON
  digitalWrite (BT_P3_RLY_R3,         HIGH);  
  digitalWrite (SOLAR_P4_RLY_R4,      LOW);  //ON
  digitalWrite (HP_HEAT_CALL_RLY_R5,  HIGH);  

  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("Solar -> DHW"));
  lcd.setCursor(0,1);  
  lcd.print(F("R2 & R4 ON"));  
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS   


  START_T        =  (readSensor_F (DHW_tank_sensor)); 
  START_T = 131;  //debug 
  
  
  //for (I=0; I< 120; I++)   //delay up to 20 min. before testing gain
  for (I=0; I< 1; I++)       //debug
  {
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 

  DHW_tank_temp = (readSensor_F (DHW_tank_sensor));
  DHW_tank_temp = 131;  //debug 
  
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("DHW TANK = "));
  lcd.print(DHW_tank_temp);  
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS           
 
  if ( DHW_tank_temp >= DHW_tank_target_temp_pot ) {goto DHW_HOT;}  
  }  //end delay loop
  

  NOW_T        =  (readSensor_F (DHW_tank_sensor));
  NOW_T = 131;  //debug FORCE DOWNSHIFT 1
  
  if ( NOW_T >  START_T )  //Gaining temp?
  {
  DHW_DOWNSHIFT_BOOL1 = false; 
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("DHW_SHIFT1=FALSE"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS      
  }  
  else
  {
  DHW_DOWNSHIFT_BOOL1 = true;  
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("DHW_SHIFT1=TRUE"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS        
  }  //end if gaining temp
  
  }  //end if Solar Hot enough for direct heating


 
  //Is Solar Hot enough for HP  -> DHW
  //AND Is DHW Downshift Bool2 false
  //AND Is DHW HP SKIP Switch Off
  else if (( SOLAR_tank_temp >= Solar_med_cntl_temp_pot ) 
            && ( DHW_DOWNSHIFT_BOOL2 == false )
            && ( DHW_HP_SKIP_BOOL ==  false )) 
  { 
  digitalWrite (BO_HEAT_CALL_RLY_R1,  HIGH);
  digitalWrite (DHW_P2_RLY_R2,        LOW);  // HP  -> DHW
  digitalWrite (BT_P3_RLY_R3,         HIGH);  
  digitalWrite (SOLAR_P4_RLY_R4,      HIGH);
  digitalWrite (HP_HEAT_CALL_RLY_R5,  LOW);  //HP ON 

  lcd.clear();                     
  lcd.home (); // go home
  lcd.print(F("HP -> DHW"));
  lcd.setCursor(0,1);  
  lcd.print(F("R2 & R5 ON"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS   

  START_T        =  (readSensor_F (DHW_tank_sensor)); 
  START_T = 132;  //debug 
 
  
  //for (I=0; I< 120; I++)   //delay up to 20 min. before testing gain
  for (I=0; I< 1; I++)       //debug
  {
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
  
// if (digitalRead(HP_ALIVE) == LOW) {goto DHW_SHIFT2;}   debug

  DHW_tank_temp = (readSensor_F (DHW_tank_sensor));
  DHW_tank_temp = 132;  //debug 
  
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("DHW TANK = "));
  lcd.print(DHW_tank_temp);  
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS
 
  
  if ( DHW_tank_temp >= DHW_tank_target_temp_pot ) {goto DHW_HOT;}  
  }  //end delay loop
  

  NOW_T  =  (readSensor_F (DHW_tank_sensor)); 
  NOW_T = 132;  //debug Force DOWNSHIFT 2
  

  if ( NOW_T > START_T )  //Gaining temp?
  {
  DHW_DOWNSHIFT_BOOL2 = false; 
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("DHW_SHIFT2=FALSE"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS      
  }  
  else
  {
  DHW_SHIFT2:
  DHW_DOWNSHIFT_BOOL2 = true;  
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("DHW_SHIFT2=TRUE"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS           

  }   

  }  //end if Solar Hot enough for HP  -> DHW

  }  //end if SOLAR HP SKIP = OFF
  
  
  
  if (( SOLAR_HP_SKIP_BOOL == true ) 
    or
     (( DHW_DOWNSHIFT_BOOL1 == true ) && ( DHW_DOWNSHIFT_BOOL2 == true ))
    or    
     (( DHW_DOWNSHIFT_BOOL1 == true ) && ( DHW_HP_SKIP_BOOL == true )))
     
  {                                                //  BOILER -> DHW     
  digitalWrite (BO_HEAT_CALL_RLY_R1,  LOW);  //ON
  digitalWrite (DHW_P2_RLY_R2,        LOW);  //ON
  digitalWrite (BT_P3_RLY_R3,         HIGH);  
  digitalWrite (SOLAR_P4_RLY_R4,      HIGH); 
  digitalWrite (HP_HEAT_CALL_RLY_R5,  HIGH);  
  
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("Boiler -> DHW"));
  lcd.setCursor(0,1);  
  lcd.print(F("R1 & R2 ON"));  
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS           
  
  
  //for (I=0; I< 60; I++)   //delay 10 min
  for (I=0; I< 1; I++)     //debug
  {
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS           
  }

  DHW_tank_temp  =  (readSensor_F (DHW_tank_sensor));
  
  DHW_tank_temp = 140;  //debug 
  
  if ( DHW_tank_temp >= DHW_tank_target_temp_pot ) {goto DHW_HOT;}  

  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("DHW TANK = "));
  lcd.print(DHW_tank_temp);  
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS
  
  }  //end if BOILER -> DHW


  
  
  } while ( DHW_tank_temp < DHW_tank_target_temp_pot ); 
 

  }  //end if if DHW needs to start heating


  DHW_HOT:
  DHW_DOWNSHIFT_BOOL1 = false;  
  DHW_DOWNSHIFT_BOOL2 = false;  

  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("DHW is Hot"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS
    
  digitalWrite (BO_HEAT_CALL_RLY_R1,  HIGH);  //turn off relays
  digitalWrite (DHW_P2_RLY_R2,        HIGH);
  digitalWrite (BT_P3_RLY_R3,         HIGH);
  digitalWrite (SOLAR_P4_RLY_R4,      HIGH); 
  digitalWrite (HP_HEAT_CALL_RLY_R5,  HIGH);  
  
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("TurnOff all Rlys"));  
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS

[buffalobillpatrick]

Main Loop part 2

     
  // Buffer Tank Control Code
  WINTER_SW_BOOL = true;    //debug
  
  if (WINTER_SW_BOOL == true) //Run this section if Winter Sw is ON
  { 

  DHW_tank_temp  =  (readSensor_F (DHW_tank_sensor));
  
  DHW_tank_temp = 137;  //debug DHW HOT STAY HERE
  
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("DHW TANK = "));
  lcd.print(DHW_tank_temp);  
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS

  
  if (( DHW_tank_temp ) < ( DHW_tank_target_temp_pot - DHW_delta_pot ))                                          
  { 
  BT_DOWNSHIFT_BOOL1 = false;  
  BT_DOWNSHIFT_BOOL2 = false;
  
  lcd.clear();
  lcd.home ();                       //BREAK OUT OF BT CODE
  lcd.print(F("GOTO DHW CODE"));     //GOTO DHW CODE
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS
  
  goto DHW_CODE;
  }  
     
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("DHW HOT"));
  lcd.setCursor(0,1);   
  lcd.print(F("RUN BT CODE"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS

  
  OUTDOOR_temp = (readSensor_F (OUTDOOR_sensor));
  
  OUTDOOR_temp = 57;    //debug

  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("OD Temp = "));
  lcd.print(OUTDOOR_temp);
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS  
 
    
  // Calculate Buffer Tank Target Temp based on ODR parameters
  BUFFER_tank_target_temp = 
  ( BUFFER_tank_lo_limit_pot +
  (( OUTDOOR_hi_control_temp - OUTDOOR_temp ) * ODR_ratio ));
  
    
  BUFFER_tank_temp = (readSensor_F (BUFFER_tank_sensor));
  
  BUFFER_tank_temp = 79;  //debug
  
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("BT Tgt  = "));
  lcd.print(BUFFER_tank_target_temp);
  lcd.setCursor(0,1);  
  lcd.print(F("BT Temp = "));  
  lcd.print(BUFFER_tank_temp);
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS  

  
  //Test if BT needs to start heating
  if ( BUFFER_tank_temp < ( BUFFER_tank_target_temp - BUFFER_delta_pot )) 
  {
  lcd.clear();
  lcd.home (); // go home 
  lcd.print(F("BT NEEDS HEAT"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
 
    
  do    //while BUFFER_tank_temp < BUFFER_tank_target_temp_pot
  {


  
  if (SOLAR_HP_SKIP_BOOL == false)
  {                              //Run this section if SOLAR HP SKIP is OFF
      
      
  SOLAR_tank_temp = (readSensor_F (SOLAR_tank_sensor));
  
  SOLAR_tank_temp = 140;  //debug
   
  lcd.clear ();
  lcd.home (); // go home 
  lcd.print(F("Solar Tank = "));
  lcd.print(SOLAR_tank_temp);
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS

  
  //Is Solar Tank is hot enough for Solar -> BT, Direct 
  //AND Is BT Downshift Bool1 false  
  if (( SOLAR_tank_temp >= 
      ( BUFFER_tank_target_temp + (BUFFER_delta_pot * 5))  
      &&
      ( BT_DOWNSHIFT_BOOL1 == false )))     
  {  
  digitalWrite (BO_HEAT_CALL_RLY_R1,  HIGH);
  digitalWrite (DHW_P2_RLY_R2,        HIGH);
  digitalWrite (BT_P3_RLY_R3,         LOW);   //ON
  digitalWrite (SOLAR_P4_RLY_R4,      LOW);   //ON
  digitalWrite (HP_HEAT_CALL_RLY_R5,  HIGH);  
     
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("SOLAR -> BT"));
  lcd.setCursor(0,1);  
  lcd.print(F("R3 & R4 ON"));       
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS
  
  
  START_T = (readSensor_F (BUFFER_tank_sensor));   
  START_T = 80;  //debug 


  for (I=0; I< 1; I++)       //debug  
  //for (I=0; I< 180; I++)   //delay up to 30 min. before testing gain
  {
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS 

  BUFFER_tank_temp = (readSensor_F (BUFFER_tank_sensor));
  BUFFER_tank_temp = 80;  //debug 
  
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("BT Temp = "));
  lcd.print(BUFFER_tank_temp);  
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS
  
  if ( BUFFER_tank_temp >= BUFFER_tank_target_temp ) {goto BT_HOT;}  
  }  //end delay loop


  NOW_T   =  (readSensor_F (BUFFER_tank_sensor)); 
  NOW_T = 80;  //debug FORCE DOWNSHIFT 1
 
 
  if ( NOW_T > START_T )  //Gaining temp?
  {
  BT_DOWNSHIFT_BOOL1 = false; 
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("BT_SHIFT1=FALSE"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS      
  }  
  else
  {
  BT_DOWNSHIFT_BOOL1 = true;  
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("BT_SHIFT1=TRUE"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS        
  }     
  
  }  //end if Solar Hot enough for Direct Heating


  //Is Solar Tank is hot enough to run HP -> BT 
  //AND Is Downshift Bool2 false
  else if (( SOLAR_tank_temp >= Solar_lo_cntl_temp_pot ) 
           && 
           ( BT_DOWNSHIFT_BOOL2 == false ))   
  {
  
  digitalWrite (BO_HEAT_CALL_RLY_R1,  HIGH);
  digitalWrite (DHW_P2_RLY_R2,        HIGH);
  digitalWrite (BT_P3_RLY_R3,         LOW);   //ON
  digitalWrite (SOLAR_P4_RLY_R4,      HIGH);
  digitalWrite (HP_HEAT_CALL_RLY_R5,  LOW);  //HP ON 
  
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("HP -> BT")); 
  lcd.setCursor(0,1);  
  lcd.print(F("R3 & R5 ON"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS  
  
  START_T   =   (readSensor_F (BUFFER_tank_sensor)); 
  START_T = 81;  //debug 
 
  
  //for (I=0; I< 180; I++)   //delay up to 30 min. before testing gain
  for (I=0; I< 1; I++)       //debug
  {
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS custom_delay_5sec();        //Delay 5 sec. & Check for GAS 
  
 // if (digitalRead(HP_ALIVE) == LOW) {goto BT_SHIFT2;}   //debug

  BUFFER_tank_temp = (readSensor_F (BUFFER_tank_sensor));
 
  BUFFER_tank_temp = 81;  //debug 
  
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("BT Temp = "));
  lcd.print(BUFFER_tank_temp);  
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS
  
  if ( BUFFER_tank_temp >= BUFFER_tank_target_temp ) {goto BT_HOT;}    
  }  //end delay loop
 

  NOW_T    =    (readSensor_F (BUFFER_tank_sensor)); 
  NOW_T = 81;  //debug FORCE DOWNSHIFT 2
 
 
  if ( NOW_T > START_T )  //Gaining temp?
  {
  BT_DOWNSHIFT_BOOL2 = false; 
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("BT_SHIFT2=FALSE"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS      
  }  
  else
  {
  BT_SHIFT2:
  BT_DOWNSHIFT_BOOL2 = true;  
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("BT_SHIFT2=TRUE"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS        
  } 
  
  }  //end if Solar Hot enough for HP  -> BT
  
  }  //end if SOLAR HP SKIP = OFF

  
  
  
 if ((SOLAR_HP_SKIP_BOOL == true) 
     or
     ((BT_DOWNSHIFT_BOOL1 == true) && (BT_DOWNSHIFT_BOOL2 == true)))
       
                              //Solar tank < minimum temp
  {                           // use boiler to heat Buffer Tank   
  digitalWrite (BO_HEAT_CALL_RLY_R1,  LOW);  //turn on Boiler Heat Call R1
  digitalWrite (DHW_P2_RLY_R2,        HIGH);
  digitalWrite (BT_P3_RLY_R3,         LOW);  //ON
  digitalWrite (SOLAR_P4_RLY_R4,      HIGH); 
  digitalWrite (HP_HEAT_CALL_RLY_R5,  HIGH);  

  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("Boiler -> BT"));
  lcd.setCursor(0,1);  
  lcd.print(F("R1 & R3 ON"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS        


  BUFFER_tank_temp = (readSensor_F (BUFFER_tank_sensor));
 
  BUFFER_tank_temp = 90;  //debug
  
  if ( BUFFER_tank_temp >= BUFFER_tank_target_temp ) {goto BT_HOT;}    
  
  
  lcd.clear();
  lcd.home (); // go home  
  lcd.print(F("BT Temp = "));
  lcd.print(BUFFER_tank_temp);  
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS
  
  }  //end if Boiler -> Buffer Tank


  } while ( BUFFER_tank_temp < BUFFER_tank_target_temp ); 


  }  //end if BT Needs Heat

  
  BT_HOT:
  lcd.clear();
  lcd.home (); // go home 
  lcd.print(F("BT HOT ENOUGH"));
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS     

  
  BT_DOWNSHIFT_BOOL1 = false;  
  BT_DOWNSHIFT_BOOL2 = false;  

  
  digitalWrite (BO_HEAT_CALL_RLY_R1,  HIGH);  //turn off relays
  digitalWrite (DHW_P2_RLY_R2,        HIGH);
  digitalWrite (BT_P3_RLY_R3,         HIGH);
  digitalWrite (SOLAR_P4_RLY_R4,      HIGH); 
  digitalWrite (HP_HEAT_CALL_RLY_R5,  HIGH);  

  lcd.clear();
  lcd.home (); // go home 
  lcd.print(F("TurnOff all Rlys"));  
  custom_delay_5sec();        //Delay 5 sec. & Check for GAS



  Serial.println(F("..................................."));

       
  }  //end if Winter switch = true
  
  
} //end forever loop

[buffalobillpatrick]

Functions:

int readSensor_F (const byte which_sensor)
{   
  #define sample_cnt 100
  
  float alpha =   0.9;     // factor to tune
  float average = 0.0;
  
  int I;
 
  float steinhart;

// resistance at 25 degrees C
#define THERMISTORNOMINAL 10000

// temp. for nominal resistance (almost always 25 C)
#define TEMPERATURENOMINAL 25

// The beta coefficient of the thermistor (usually 3000-4000)
#define BCOEFFICIENT 3892

// the value of the series resistor
#define SERIESRESISTOR 10000




  digitalWrite (mux_enable, HIGH); //disable
  delay(10);

  // select correct MUX channel
  digitalWrite (mux_address_A, (which_sensor & 1) ? HIGH : LOW);
  digitalWrite (mux_address_B, (which_sensor & 2) ? HIGH : LOW);
  digitalWrite (mux_address_C, (which_sensor & 4) ? HIGH : LOW);
  digitalWrite (mux_address_D, (which_sensor & 8) ? HIGH : LOW);

  digitalWrite (mux_enable, LOW); //enable
  delay(10);


  
  for (I=0; I< sample_cnt; I++) 
  {  
  average =  alpha * analogRead(mux_analog_in) + (1-alpha) * average;
  delay(10);
  }
 
  // convert the value to resistance
  average = 1023 / average - 1;
  average = SERIESRESISTOR / average;
  steinhart = average / THERMISTORNOMINAL;     // (R/Ro)
  steinhart = log(steinhart);                  // ln(R/Ro)
  steinhart /= BCOEFFICIENT;                   // 1/B * ln(R/Ro)
  steinhart += 1.0 / (TEMPERATURENOMINAL + 273.15); // + (1/To)
  steinhart = 1.0 / steinhart;                 // Invert
  steinhart -= 273.15;                         // convert to C
  
  return (round(steinhart * 1.8) + 32);       // round to whole number 
                                              // & convert to F            
}  // end of readSensor_F




void custom_delay_5sec (void) //Delay 5 sec. & Check for GAS 
                         // If so, RESETS RLYS, Sets ALARM, & HANGS FOREVER
{  
 int I;
   
  //T1 = millis();  //This takes 1.8us
  
  delay(3965); 


  //Test if GAS LIMIT EXCEEDED
  sensor_data  =  (readSensor_F (MQ2_GAS_sensor));
  
  sensor_data  =  map(sensor_data, 0, 1023, 0, 100);
  
  if (sensor_data > GAS_LIMIT)     
  {  
  digitalWrite (BO_HEAT_CALL_RLY_R1,  HIGH);  //turn off relays
  digitalWrite (DHW_P2_RLY_R2,        HIGH);
  digitalWrite (BT_P3_RLY_R3,         HIGH);
  digitalWrite (SOLAR_P4_RLY_R4,      HIGH); 
  digitalWrite (HP_HEAT_CALL_RLY_R5,  HIGH);  
    
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("GAS LIMIT MET"));
  lcd.setCursor(0,1);  
  lcd.print(F("TurnOff all Rlys"));  
  delay(5000);
   
  lcd.clear();
  lcd.home (); // go home
  lcd.print(F("HANG FOREVER"));

  do{ beep(200);} while (I == I);  //hang  
  }  //end if GAS LIMIT 

/*
  T2 = millis();

  TT = T2 - T1;
  
  lcd.clear();
  lcd.home (); // go home
  lcd.print(TT);    // 5 sec
  delay(10000); 
*/


  }  //end custom_delay function  



void beep(unsigned char delayms)
{
  analogWrite(ALARM, 255);     // Almost any value can be used except 0 
                           // experiment to get the best tone
  delay(delayms);          // wait for a delayms ms
  analogWrite(ALARM, 0);       // 0 turns it off
  delay(delayms);          // wait for a delayms ms   
}

[AC_Hacker]

Hey BBP,

I'm not sure just how your heat pump controller setup is arranged.

I believe you indicated that you have three Uno's working together, is that right?

But I don't know which is doing what, and how are they co-ordinated.

Do you have some kind of top level diagram that explains your setup?

-AC

[buffalobillpatrick]

2 Arduinos in Heating system. (I play with more)

Master powers up Slave HP Controller via R5 when HP is needed, or powers off Slave when not.

Slave tells Master that it is powered on & functioning via "HP ALIVE Signal" which is active within 10 seconds of its Power On.

This is done in Slave by energizing ALIVE_RLY_R1 via its pin D4

The Slave frequently calls its custom_delay function,
which: Delays 5 sec. & Checks Source Out water temperature & GAS Level inside HP

If GAS LIMIT is EXCEEDED, then Audible Alarm is activated & ALIVE_RLY_R1 is reset via pin D4.

or if Source out is too cold to run HP, then ALIVE_RLY_R1 is reset via pin D4.

The Master reads this "HP ALIVE Signal" on its pin D12
in its code after powering On Slave

if "HP ALIVE Signal" is found to be "OFF"
then the Master powers off Slave by de-energizing R5

and "Downshifts" from using HP to using Boiler.

[AC_Hacker]

Just to make sure I'm working within the bounds of a cheap DIY heat pump controller, I bought the cheapest Arduino Uno clone that I could find.

I got mine HERE, for $6.94, free shipping. There are plenty of other choices at similar prices.

This photo compare it to my older Arduino (right), but I compared it to a diagram of a real Uno, and it compares favorably, but maybe with a few improvements...

The clone has a row of plated-through holes that are inboard of the shield-mounting sockets. These holes could make it handy to attach leads to and from analog & digital I/O devices.

The reset switch has been locate to the edge of the board, very handy, plated-through holes are available for a serial hookup.

When I hooked the clone to my PC, I got a message that a driver was required, and the automatic driver search for failed.

Then I thrashed about on the Internet until I finally found one HERE.

The ZIP contains some bizarre Chinese utility that I couldn't figure out, but there is a folder that does do the job. I juat attempted to upload just the correct utility, but it exceeded the meager allotment of bytes (sorry guys).

Anyway, the driver worked, even on my Win7_64 system, and I'm off & running.

I tried loading up Ko_deZ Heat Pump Controller sketch, and all seems well.

Now, on to some real software...

-AC

[AC_Hacker]

I thrashed around trying to get the LCD-button display working, and it wouldn't...

So I downloaded the newest stable Arduino IDE, and tried again and everything
is working just fine.

It was easier getting the display to work than it was taking a photo of the working display. Seems to have something to do with polarized light, because I had to take this photo through the lense of some polarizing sunglasses, with the lens rotated "just so" in order for the characters to show up properly.

To the eye, the characters are quite nice and visible and very easy to read.

* * *

So jeff5may, it's time to start working with the menu software you cooked up.

Can you just drop it into a "CODE" window here in the thread??

-AC