I have an old polynesian hot tub s/n 233814 and it says the model is "Appian". I have all of the original books and paperwork and it looks like it was made in 1987. It is 120 volts. It has been working great and I have only needed to replace the water pump seal in the past. The seal is leaking again so I will be doing that soon. I noticed over the last several days the temp. has been dropping. My temp. gauge doesn't work anymore so I can only guess at what it dropped to. In the troubleshooting section of the manual it says if the red light is on and you are getting no heat the heating element is bad and needs to be replaced. I can hear an audible click noise when the the red light comes on when I turn the dial. I'm going to pull the filter tonight and see if that helps. I also noticed the brass fitting the heater element screws into is warm to the touch when it's running. The blowers and everything else works ok. I'm looking for advice on this problem and also where to find an analog replacement temp. gauge. Mine rusted and fell apart.