That appears to be a bad LED. Did you try swapping it with another one?
Output port 3 will only do PWM with an analogWrite() command. You are using digitalWrite() commands so PWM does not apply here.
You have the baselineTempt is set high (28.7 C). Unless it's very warm where you are, that could be why you have a harder time increasing the temperature. The baselineTempt should be changed to your local room temperature.