If you open up the outside access door you will see a Red LED light on a black box. That is the Temp sensor control. Li-op is the same code as NO CO. Your Box is wired thru the main control board so will show Li-op. You state it is raining. See if the rear area of the refer and that box has water on it. THAT will trip the boxes. The only recourse you have is to do the Magnet trick. The other is NOT a good idea---bypassing the control box. As another stated, the Limit system is there for SAFETY. In normal operation, it will trip and shut the refer down when the flue area gets over 700 degrees. The normal temp is around 350 degrees. The correct safe procedure when this Li-op happens is to have the refer and system checked by a qualified Norcold technician to verify there is NOT a safety hazard and the system did its job. Doug