While I didn't need instructions to install the device, the Thermostat itself is variable, and needs to be set in order to avoid major issues ranging from poor performance or early failure to a fire... After scouring the internet I found the unit has a range of 135 to 155 degrees Fahrenheit. Setting A = 135, B = 140, C = 145, D = 150, and E = 155 degrees. I will gladly pay the extra 50 cents for a guide thank you. What should have been a half hour fix, turned into a 2 hour event. Hope this helps the next buyer.