I have lived in this house for 10 years and every year I have my furnace cleaned and checked. This year no exception, all of a sudden the pilot light just shuts off, I have had the thermocouple replaced the thermopile has been replaced. I have cleaned it, this is a very random problem. It may go for several days and not go out and then it will be an everyday occurrence. I am baffled and so is my serviceman. What about the Register limit switch or the Primary limit switch... Please help. Thank you

Normally limits won't cause a pilot to go out, just the main burner. Has the pilot burner been cleaned or replaced? What is the voltage output of the thermopile? You have both a thermocouple & thermopile? Very unusual.