So I joined this site to learn more about programming and possibly create some devices that I could find useful. Unfortunately I find it extremely hard to learn much from here, most is way over my head . on top of that , finding a useful idea to learn from is the other caveat .
So I decided on something that would be useful to me and want to try to use it to actually learn something of value. So here is what I am trying to create;
I have a Fireplace Extrodinair 36 elite that has a fan speed control connected to a snap switch  that is strictly on/off (90 off,140,on). The problem is that the control is very rough, because it doesn’t really monitor temperature well. Many times I have a fire and the fan kicks on and blows cool air. I then have to turn off the fan , let it heat up then manually turn it back on. As far as I know the fan speed control seems to be working correctly , just the temperature control is the issue.
What I would like to do is use an ESP (8266,ESP32) or some device that would monitor the heat in the air chamber and turn the fan on or off at a predetermined temperature. I would use a Wheatstone bridge and a RTD to do that function as far as varying the speed of the motor I am totally lost seeing how the speed pot is mounted to a circuit board and not understanding how it varies the speed . I assume it is just adjusting voltage but don’t know, hoping that I could create a circuit that would work wireless and also show on a web page reading .I have looked and built the ESP webpage that would post temp, humidity and so on but haven’t really learned or understood enough to even get a decent start.
Thanks to all that have read this.

Hi Larry.
In summary, what would you like to know?
It  is better to divide your project into small steps, try to learn what you need to achieve those mini steps, and then, finally, try to put everything together.
Regards,
Sara

     So ok , my frustration comes from not knowing how to combine parts of programs because they usually fail when doing that. In the code the parts are scatted all over for the most part and not really understanding how the code is working . 
         Not sure how I would control the speed because there is a rheostat tied to the 120v capacitor on the motor ,so probably won’t be able to used the ESP to control speed.
     What I would like to do is read temperature of the fireplace air chamber (not in the flame) , display it , also monitor it on the web and control the fan on off with temperature. What is happening currently is that the snap limit switch will turn on the fan erratically so instead of heat it will blow cool air. 
     I have replaced the limit switch to a more improved one, still not much difference, replaced the rheostat with a new one .So I know that it isn’t a issue with devices , more so it is control.
      I know I should be considering using a RTD and Wheatstone bridge  to obtain the temperature readings , DHT just won’t be able to hold up to the fire box temps without melting .
 
 
 
 
 

Hi again.
 
To read the temperature on the gas chamber I recommend using something like a thermocouple that can handle high temperatures. For example: K-Type thermocouple with Amplifier
 
You can build a web server to display the temperature. We don’t have any example for that specific sensor, but we have many tutorials about web servers. For example, I think the following tutorial might be useful: https://randomnerdtutorials.com/esp32-esp8266-thermostat-web-server/
 
To control the switch you can use a relay, depending on how the switch is structured. We also have tutorials about relays.
 
You can use the search box on our website to search for specific topics: https://randomnerdtutorials.com/
 
Regards,
Sara
 

     Thanks, I am aware of the web server program and have been playing around with it a bit, to be honest, the code is over my head . 
     As far as a relay I plan on using some dc switched  ss relays I have but would really like to be able to control fan speed. As temperature rises fan speed could be adjusted. This could help with the cooler air from fireplace . 
     Was thinking about cold junction thermocouple that I can make from thermocouple wire I have lying around. 
     As use I need to put more effort into research and really do appreciate your input. Thanks again