Since we have had this unit (5 years), pilot light went out regularly, servicemen turned it up, and some months ago, thermocouple was replaced and ran until this week (extr. windy day) when went out AGAIN and cannot be relit. Following instructions in Owner Manual for such, but it won't stay lit. We have manual switch on/off which is fine, but once pilot blows out, it is impossible! Not happy with this unit. Your experiences....?