I have a:

2005 Coleman Spa
Model 471 Sierra
220 Volts
Serial Number 471060201596
Duel Pumps

My problem is:

The LCD Panel on the top side says that the water temperature is 104 degrees. BUT, it is only 99 degrees.

Since the maximum temperature is 104 there is no way to increase it higher. Is there something that I can check myself (before I have to call a repairman). It seems like it would be something simple......Maybe, somehow increase something on the heater its self. I have not taken off the skirting to look at the heater. I thought I would wait to see if someone might be able to tell me what they think might be wrong. It is like the heater might need to be adjusted.......

Please help....... I purchased this used about 3 months ago and it has always been like this. It is actually still under warranty, BUT since I am the second owner, it is not transferrable (I don;t think). The prior owner gave me all the paperwork, including the warranty and the actual purchase receipt.

This may be a dumb question, but are you sure it's only 99? Be sure the thermometer you're using is accurate, and not a lousy pool thermometer.