Just bought an old Leisure Bay 3man tub with an AP1400 SpaBuilders Pack and Topside control. Set thermostat at lowest setting and ran it for 48 hours with no problems but once it heated up the high limit switch activates. I have noticed that the low speed pump never shuts off. Even with the switch on economy heat and the timers set, it still runs along with the circulation pump. I have noticed that the pump is mighty hot to the touch after the high limit switch activates but the heater housing is hardly warm. The heater has to be working because the water warmed up after the first 24 hours. Like I said the tub worked excellent for the first 48 hours but then strted activating the high limit switch. It takes a while for it to activate (hours). I cannot get the low speed pump to stop unless i pulll the plug. Even when it is not on the filter cycle, it is still running. Any ideas?? " title="Rolling Eyes" />

The relay to the low speed is likely stuck. If the relay is exposed, look at to see if it's closed. If it's enclosed, it can be popped open. You can also use a meter to test it for continuity or ohm.

The relay is open and when i manually close it, nothing changes.