ESP8266 Gas Boiler Controls over thermostat wiring via smartphone (blynk app), web (api), physical button.

This is C++ code to run on ESP8266 (platformio IDE used) as simple control unit to switch on/off generic gas boiler via thermostat wiring.

Getting Started

In order to use this code u must have some basic skills in electronic's field. If you dont - stop. There is risk of getting shocked or damaging gas boiler.

Most of Gas Boilers on the market can be controlled via thermostat wiring (2 wires). The idea is dead simple:

• Wires shorted - gas boiler works.
• Wires arent connected - gas boiler stops.

In case u have double-pressure boiler as I do, second heating circuit for waterflow is not affected by thermostat wiring.

Thermostat wiring itself does not control the maximum temperature u getting off your gas boiler. It will heat the water, until threshold is reached. Water temperature threshold is set directly on a gas boiler.

Thermostat devices collect air temperature and turn on/off gas bolier pereodically to maintain desired temperature. This unit itself does not implement such logic, since I will be collecting air temperature metric from another ESP8266 device.

Prerequisites

You will need following parts to get it working

1. ESP8266 board
2. Resistors 100 Ohm, 1 KOhm.
3. Optocoupler 817c or similiar.
4. Led diod
5. Non-fixed push button (You cant use fixed buttons and have device controlled)

Deployment

• Copy credentials_sample.h to credentials.h, define constants, accroding to your enviroment
• config.h has some optional setting, feel free to edit as you wish
• Upload FW to esp8266, make sure it's reachable over WEB
• Do the wiring according to scheme below
• Setup your blynk app (defaults State LED - Virtual Pin 0, Button - Virtual Pin 1)

Schema

API

Request	Description
/api/boiler/on	Turns ON Gas Boiler
/api/boiler/off	Turns OFF Gas Boiler
/api/boiler/invert	Inverts previous state, ON-OFF or OFF-ON
/api/boiler/status	Gets current state

Typical JSON response is

{
    "state": true
}

Contributing

Feel free to discuss and contribute.

Authors

• Konstantin Odnoralov - Initial work -

License

This project is licensed under the MIT License.