I have a residential Raypak 105WT, installed in 1990. The high limit control is a black dial and the temp sensor is at the end of a copper line and extends into the cabinet. I had the limit control set at 125 or so. One day we came home to find the heat off, and I checked the water temp - it was at 60 degrees!.. I turned up the dial on the hi-limit, heard a click and then it turned on! Do you think I need a new sensore or a new control? I wouldn't mind a manual either, but I can't seem to find it online.