page_title: Griddle
section_title: Snap-action
hierarchical_section_title: Griddle / Commercial / Temperature control / Thermostatic / Snap-action
context_page_description: A griddle is a cooking device consisting of a broad flat surface heated by gas, electricity, wood, or coal, with both residential and commercial applications. In industrialized countries, a griddle is most commonly a flat metal plate, elsewhere typically a brick slab or tablet.
  A residential griddle may be composed of chrome steel, aluminum, or carbon steel. The vast majority of commercial grade griddles are made from A36 steel, though some are stainless steel or composites of stainless and aluminum. Almost all residential and commercial griddles are heated directly or indirectly by flame or electrical elements.
context_section_description: Snap action thermostats are the most common control used in heavy duty commercial griddles with medium-to-heavy production demands. These controls are called “snap action” because the control mechanism will turn the burner valve or electrical element fully on or completely off, with no modulation or intermediate heat source operation – effectively ‘snapping’ the heat source on or off. While not as responsive as solid state controls, snap action controls can maintain a griddle surface temperature within +/- 15 °F (8 °C) of set point if the thermostat bulb is embedded assuming a 1-inch (25mm) thick steel plate. This operating temperature range may be pushed to +/- 20 to 25 °F (10 °C to 13 °C) if the probe is bottom mounted due to the additional thermal hysteresis introduced by the plate material.
  Snap action control systems are often run with electricity, where a stand-alone thermostat acting as a switch is activated by the capillary bulb fluid. The thermostat switches an electrical signal on-or-off to an associated solenoid valve, controlling gas flow to the burner. This construction allows integration of other control mechanisms into the system, such as pilot flame failure, but requires the use of components known to be sensitive to high temperatures and water damage. Solenoids and associated wiring are known to degrade over time, even if operating within their design parameters, due to the cumulative effects of thermal cycling and ambient grease and oil coating their surfaces – environmental aspects known to attack the integrity of plastics.
  Mechanical snap action thermostat valves are the integration of the control mechanism with the flow control valve. These devices have the same performance characteristics of the electrical system counterpart, but without the need for electrical wiring and the associated caveats. Pilot safety protection can also be integrated into control systems that utilize these devices, which can result in a wholly mechanical alternative to the electrical system. Appropriately designed, mechanical system are less sensitive to heat, water and grease infiltration, and so allow for a higher operating temperature range; up to 550 °F or 288 °C.
caption: Electric snap Action thermostat with solenoid valve
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