Inkmann

I just bought a used hot tub. The woman was the second owner and did not have any manuals, there is no brand-name on the tub either. The controls are marked Turbo Touch, the heating element is made by RMF. How long should it take for this to come up to temperature? It has been up and running over an hour and a half and is only come up 3°, I started out with 48° water. The heating element is not hot to the touch. Is that normal? Let me know your thoughts. Thank you John