jademann

I have the Grey Saluspa "egg" with the round green inflatable hot tub. It is about 18 months old, but has only been used in that time for 4 months. I had some E2 errors early on which I corrected with a new filter however it has recently started to not maintain temperature, it sits there are at 93F when the setpoint is 102F. I took the impeller apart but found no wear or problems with it. It was noisy but not any longer. A couple of times I turned it all off for a few days and when I switched it on it went up to 104F with 102F setting. However next morning it was back to 93F. I am thinking there must be something simple inside which is not working properly, but I don't know the internals. Any ideas what might be wrong? I have been through 3 bucket heaters, but they all fail after a few days.