for any one who might be interested, here a sketch for esp wifi relay to be controlled by my RA8875 display user interface … it based on my autoDS1820 mqtt sketch, it can control up to 8 relays controlled by 8 ds1820. it was meant for zone control for hydronic floor heating system… it also will control a normal heating equipment. but you loose several relays 2-4 relays to control cooling, heating and fan ( plus eco if you have this function)
Thermo_mqtt_esp_1_wt.zip (4.8 KB).
it also has the added benefit-- you can plug in a heck of a lot more DS1820 into it (much more then 20 though you will have to provide thier own power to do that and keep lengths under 50M). but those will not be controlled they simply transmit data automatically created Mqtt topic based on it ROM ID that you can load into the RA8875 screen. but it response will slow down 2 seconds for each ds1820 (search and flush data from onewire). the ds1820 are hot plug-able and you can add more to it with out shutting down and powering up again they will be automatically detected and start broadcasting data moments later. it also saves your preset temperature ranges. so if the power goes out it will start up again with the same temperature setting that you had before… I will provide a total sketch for the ra8875 with zone and thermostat features in a couple day as I will be gone, travelling back and forth for the next week … though the current one will work with a little adaption of the topics all I really need to do is add in controls for off/heating/cooling fan auto/fan on( though on esp that proving tricky for some reason) .
good luck have fun