18 + 15 + 18 =. 51 amps, not 47 amps. Which means your drawing more amperage than your spec plate. Why is that? Is your controller over-calculating current in the elements or is your kiln improperly specd? Another issue, i’ve Recently had to service the controller for the km1227pk kiln for my wife because it blew the transformer on a cone 5 firing. Your controller is a Nightmare to work on, and I am an engineer, so I know what I am talking about! Conductors are all the same color, nothing is marked, your mercury relays are paired to the elements (6 relays for 3 hot sections) and your wiring diagrams don’t indicate which mercury relays in the controller are paired, the only way to find out is to find which relays are assigned to the corresponding outputs from the controller board. A real amateur job, not a professional unit by a long shot. A real pain in the ass to work on! Really sucks!