Kiln switches have a very important function: they turn your kiln on and off! Switches are found on manual kilns - those without digital controllers - and over time, you will find that these switches do need occasional replacing. When you are replacing your kiln switch, it is important that you choose the proper switch. Infinite switches, or “stepless” switches, are those switches with variable power output, meaning that you can turn and adjust them in one smooth setting. These differ from “position” switches, which lock into specific positions, such as a 3-position switch with low, medium, and high settings. Some people prefer the infinite switches because they allow you to make very slight adjustments to your kiln’s elements; some people prefer the position switches, because following recorded directions to faithfully repeat a firing is easy to do with direct and specific switch positions.
Kiln relays are found in a kiln’s control box and are responsible for switching the power to your kiln’s elements on and off. That familiar ‘buzz-click’ noise that you hear when you start your electric kiln’s firing cycle comes from a relay becoming engaged. Relays are different from switches because they are more of an internal mechanism that works to transfer power to elements.The relay receives a signal from the kiln’s controller, and an electromagnet within the relay is charged. This pulls contacts together, which turns on the kiln’s elements. Like any mechanical part, relays will eventually need to be replaced due to normal wear on your kiln. If the elements will not turn on in a specific region of the kiln, it is possible that the relay responsible for controlling that region needs to be replaced. This will prevent your kiln from reaching temperature.
Mechanical relays are relatively inexpensive, small, and can be used in small control boxes. These relays, however, have a relatively short lifespan, especially after repeated exposure to high temperatures, as in firings. Mercury relays are an alternative to mechanical relays, as they are longer-lasting. The drawbacks to using mercury relays include hazards associated with handling mercury if the relay breaks, and the relatively higher cost and larger size. While most kilns come standard with mechanical relays, mercury relays are sometimes offered as an add-on.
Please note that different kiln manufacturers produce unique kiln parts. Some of these are interchangeable, while others are not.
