High Limit Temperature switch used on many electric spa and hot tub heaters. 2 Terminals, 1/4" diameter bulb. Also called an over temperature switch, or over heating switch for a hot tub or spa.
Spa and Hot Tub Applications include: Brett Aqualine, CRL, SpaTemp, Ramco, many hybrid digital/electronic controls that have a red button type over temperature switch mounted in the control box.
If your hot tub has a red reset button similar to this one, it should work.
What it will not work in: Vulcan heaters (used most often in older Leisure Bay spas with Len Gorden controls) with the small plastic box mounted in the middle of the 12" long stainless steel heater, and applications where there are 3 electrical terminals.
Application Notes: This is a simple on/off switch, that trips when a temperature range of 112 to 119 degrees is reached. After the water cools down to an acceptable range, the switch can be reset by pushing it in. When resetting, you will only hear a very tiny 'click'. You almost certainly will not feel it reset. After it has reset, there will be very little to no movement in the red pushbutton.
