If it were me , i would go to the manufactures web site, they may have info download able. If not send an email to the company(look for the ol contact links) asking them for info. If you are paranoid about letting them kn ow you have one of the cookers, then, if your ISP allows you to have multiple email adys, make one with a credible sounding name, and get em to send you a service manual.
If this fails, then I would go the trial and error route, using probally boiling DH2O, and allowing for altitude calibrate it, or for higher temps a good accurate glass thermomemter and some cooking oils.
If you set the temp on the front to say 130C and it gets to only 115, you trial and error . You will work it out eventually.
Good luck