This project is based on the Arduino mini and miniENC ethernet module. Both are cheap and are easy to find. The server has a Nokia 3310 LCD to monitor the actual temperature values for the boiler and burner. It usesPCB two MAX31865 with PT1000 to sense the temperature of the burner and the boiler. On the server's PCB there are three potentiometers PCBrs to adjust the a) pump start temperature, b) max boiler temperature c) delay time for the start and stop. Server and client must have IPs into the same network and you can use the NAT of your router to monitor your thermostat form the internet. Because of the small rom size of the Arduino nano, there are only "some" bytes for the web page. you can use an Atmel with more memory to have a better-looking web page.
Why this thermostat ?
A popular way to produce hot water is “the sun”. In winter (let's say November through March), hot water is produced by the burning of diesel. The burner stops at 60 degrees. (After three starts the burner stops at 60 degrees but the temperature will reach about 70degrees.) - After one year of use: the best hot water temperature that balances temperature and diesel cost is 52 -The hot water pump starts at 40 degrees. The maximum temperature in the hot water tank is set to 60 degrees. (1500 liters of hot water is enough for 6 apartments). The pump starts to circulate the water between the burner and the hot water tank by bringing the hot water temperature from ambient temperature to 60. After reaching the desired temperature in the hot water tank, the pump continues to run. There is a difference of about 10degree that the burner’s boiler temperature must drop down to start the burner again. Once the burner is switched off and starts to cool down amounts of heat are transferred from the hot water tank to the burner’s boiler. The pump, if the temperature is greater than 40 degrees, continues to run. Here the digital thermostat stops the pump to run when it detects that the temperature of the hot water tank is higher than the burner temperature If users use hot water and temperatures resist, the digital thermostat allows the pump to operate again.
More theory and reading:
More about you can read on the story of my project Digital Thermostat with a remote monitor.