Never found out what the problem was. My dealer never could find the problem after 3 trips. The last couple of trips we took the heater worked just fine. They did tell me that if it happen again to take off the outside heater cover and look on the PC Board for a red LED error code. They said if they had the code they would know what was causing the problem and could fix it. I'm guessing my problem was with dust and debris that finally either blew away or burnt up.