Hi Limit Protection Switch

The high limit switch in a hot tub is a safety feature that prevents the hot tub from overheating. It is usually located near the heater, often on the heater housing or near the control panel. The high-limit switch measures the water temperature by either a capillary tube attached to a bulb or a mounted sensor. When the hot tub water reaches unsafe temperatures, typically around 110 or 120 degrees Fahrenheit, the high limit switch will open in order to break the circuit, preventing the heater from having a meltdown in cases of equipment failure.

If a high-limit switch fails, it can lead to several problems:

1. Heater Dry Fire or Overheat Condition: The purpose of the pressure switch is to monitor water pressure inside the heater tube and ensure it is full of water and circulating properly. If it fails, it could lead to a heater dry fire or overheating condition.

2. Improper Heating: If the switch is open, the spa will not heat as it is not sensing proper water pressure in the heater tube.

3. Potential Damage: Although it rarely happens, if a hot tub heater were to run without water moving through it due to a failed pressure switch, a massive meltdown or fire could result.

4. Error Codes or Complete Shutdown: If the High Limit is causing your no/low heat, it will usually trigger an error code on the display or the heat indicator will blink. High-limit errors often shut the whole tub down so even the jets don’t work.

Therefore, it’s crucial to ensure that the high-limit switch in your hot tub is functioning correctly for safe and efficient operation.