Hello there! To start, I am completely new to all of this. I have never dabbled with electronics, but I am a certified electrical contractor so I understand some of it - maybe.
Basically what I want to do, is make a better multi-stage temperature controller for my field of work, and produce a product that I can sell. By multi-stage temperature controller I mean relays that (1, 2, 3, 4, etc) that open and closed based on a temperature sensor and a programmed temperature.
For example: I have two water heaters in this building. I connect a sensor on the outlet of the two water heaters. I program a setpoint through an interface to have a target of 130 degrees F. I will use two relay outputs from my controller, each to turn on a water heater. So let say the temperature drops to 120 degrees, heater #1 will come on and run until it reaches 130 degrees. If it cannot keep up with load, and the temperature falls to 115 degrees, heater #2 will come on to help it out. I would also need a lead lag system programmed into it, to swap between which heater is the lead and which one comes on if the lead cannot keep up.
It is fairly simple, might have other little things to add to it. But what I would like overall is to be able to control several water heaters with relay outputs, connect a couple of temperature sensors to it, and maybe have it control a pump or two.
To me this sounds like a simple idea, but I have absolutely no experience or knowledge when it comes to the electronics controller of this. I did a good amount of google searching and I kept coming back to Arduino. Is Arduino something that I could use to make a nice little control to do this? Or would something else work better? I am looking for advice and guidance because I am trying desperately to figure out where to start! I know there will be programming involved, might have to pay someone to do that for me. I do have some programming experience but very minimal.
I would be trying to keep this no larger than 5 inches tall, 5 inches wide, and 2 inches deep, and preferably smaller if possible. I would like it to have an LED or liquid crystal, or some kind of screen to be able to change setpoints and values, enable or disable relay outputs, etc.
EDIT: I guess I should add this: I know there are all kinds of temperature controllers out there, but there aren't nearly as many for commercial use as there are for residential use. I am not looking for anything residential. I work strictly commercial with water heaters much larger than you would find in a house. I install and troubleshoot these controllers almost every day. My goal is to create a simpler, cheaper, more cost efficient temperature controller that what I currently find on the market.
Does this sound feasible? Or do I just sound like a total newb? I really hope someone can help point me in the right direction!
Thank you very much for reading.