Dear fellow potters,
I just purchased and installed the Orton three zone controller for my kiln. I would like to warn anyone who is considering this.
I am generally satisfied with the controller, and Orton provided me with responsive and competent technical support. But they did not initially help me assess whether my kiln would be sufficiently powerful enough, and I am disappointerd with this.
So here is my advise. There is one major thing that you must consider before retrofitting a 3-zone controller to your kiln. Your kiln must have considerable surplus power to reach your highest working cone. And I do mean considerable.
Here's why. When you run your kiln manually, and let's say your reach your cone in the last half hour at a rate of 108 DegF\Hr. Then, assuming that you are running at full capacity to achieve this, then you will certainly not be able to maintain this same rate with the kiln controller. The controller will be switching your elements on and off as it tries to maintain even heat, so only a net percentage of your kiln's capacity will be used. Consequently, it may not even be able to reach your cone.
Because I am not an expert, I suggest this a really general guide...that if you can reach your cone reasonably by running at only half or two-thirds of your full power (such as running with only 3 to 4 elemnts out of 6 total), then it might work out okay.
If not, you'll still be able to run your kiln unattended, but you will be able to get uniformly heated zones at the end of your fire.