Heat Light Turns RedUpdated a year ago
The heat light turning red is normal during heating operation on smart control models. This normally occurs 10-15 seconds after engaging the heater. You should notice the temperature of the spa water rising 1-2 degrees per hour when the heat light is red. Once the heater reaches its set temperature, the heater light will turn green, meaning it is not engaged but is in standby mode to heat when the water temperature falls below the set temp.
On Frame series units with a top panel, the heater icon will be solidly lit when heating and will blink once set temperature is reached, showing that the heater is not engaged but is in standby mode.
Please note that the unit will actually heat the water temperature approximately .5C OVER the set temp to create a small buffer so the heater is not constantly engaged to maintain the set temperature.