I'm having a strange problem with a new Raypak r266a - electronic ignition pool heater. Here is the situation: when the heater is off, it accurately reads the pool temperature at 71 degrees. Then when the heater is turned on and set to 85, the pool temperature reading on heater display starts climbing quickly, until it reaches the setpoint of 85 and shuts off. The whole process only takes about 1 or 2 minutes. The pool water temperature has not changed obviously, but the heater thinks it has hit setpoint temperature that quickly. The pool temperature reading on the heater display then starts falling and the heater turns back on. The heater is cycling on and off constantly and not heating the pool properly.
Does anybody have any ideas what could be causing this issue? The heater is only one year old! I haven't been able to find anything related to this online.