Closed or partially closed valves or jets.
The causes of low water flow in a spa include: Eventually, the temp sensors or will detect the increased water temperature and shut everything down. When water doesn’t flow fast enough through the heater, it removes less heat, and the temperature of the water increases. Low Water Flow (LF, FLO), is the usual cause of an overheating (OH, OHH) spa or hot tub. Press any topside button to reset a digital spa after the water has cooled to 100° F. After the water cools, a high limit switch may be need to be reset on some look for a red reset button. The spa obviously should not be used when OH or OHH is flashing on the as the water could be scalding hot for several more minutes. Open the spa cover to allow excess heat and steam to escape. OH, or OHH, or OHS ( Overheat) all mean that a temperature sensor has detected unsafe water temperatures of 108° – 118° F, and your spa is in an emergency cool down mode, shutting off the heater, and turning on and to help dissipate heat. In our series on spa and hot tub error codes, we turn our attention today to the HOT messages that your topside control may be trying to give you.
