Smart controller for gas pool heaters.

Simple panel control is a built in option however the intent is remote control either through Home Assisant or a custom application. Full pool monitoring and control can be achieved when combined with a smart water pump to keep the pool in optimal conditions and remotly set state. I am using this in my Hayward H series pool heater, I do so at my own risk and take no responsibility if you use it. (Source code is in my repository available upon request)

Thermal sensing is done using 2 DS18B20 temperature sensors (One Wire Protocol), which measure intake and output water temperatures.

4 relays are used for controlling; gas valve, ignition and blower.

For safety 2 relays are used to control the gas valve (shut-off redundancy).

Flame sensing is done by reading the analog voltage from a thermopile. A standard thermopile will output 300mv to 800mv which is fairly easy to sense with the ESP32 12bit ADC. A failure of the thermopile will result in shutoff since no voltage would be sensed.

The water pressure switch is a normally open type that is common to most heaters is reused.

3 inputs are provided for front panel buttons (mode, up, down).

Connections are provided for a simple TM1637 display.

This board is intended to be powered by 24VAC (50-60HZ) since most gas valves (at least in the US) use this same voltage.