Why does my Morgan 5 person stand alone spa heat the water so much hotter than the temperature set?

SOURCE: Heater will only heat spa water to luke warm.

the water in my arctic spa hot tub took 2 weeks to get to 102 should it take that long ?

SOURCE: water temperature thermostat misread

You most likely have a bad water temperature sensor. Replace the water temperature sensor that is probably near the discharge side of the filter pump. That should take care of the problem.

SOURCE: My water temp is reading 50 degrees too high.

This is probally your temp sensor. It will be mounted in one of your pipes and held in place with a stanless steel clamp.and have a wire running back to your control box and plugs in on the low voltage side of the control. good luck.

SOURCE: the temperature on digital readout says a certain

Your temp sensor has gone bad. This is a small tube with wires coming from it. You will find this on the left side of the water manifold. Follow the wires to the front of the heater and unplug it from the temp board. Install the new one in the reverse fation. good luck.

SOURCE: Pool Heater Mis-reading Temp.

Your temp sensors are on the heater, a small tube that slides into the water manifold, usually on the left side. On the remote it will be in one of the pipes coming from the pump or the filter. If it is after the heater you should move it to between the filter and heater. It will be a tube that is in the pipe with a stanless steel clamp holding it in place.
To find out wich one it is you will need to remove the remote from the system by takeing the wires that go to it from the wireing inside the heater and wire nuting the wires in the heater together. If the heater runs normal then it is the sensor for the remote if not it is the sensor for the heater. Let me know how you do and if need be we can get a little more specfic for your system. good luck.