Good news!! Totally removed the burner assembly and cleaned with simple Green. flushed with water, then compressed air and let dry. Remove and cleaned 15 brass orifice jets with SG and pin gauge. Removed fan assembly and totally cleaned. I found dryer lint and dust in burner assembly especially. Cleaned flame rod sensor with isopropyl alcohol and put it back together...works fine now! I will try again tonight. I have this system in my radiant heat system with four zones. I also plumbed in a standard electric hot water heater in series. This gives me the option of using electricity or propane to heat my floors. With a 10 KW grid connect wind turbine, and 3.3 KW PV we have an excess generation this time of year of 3,000+ KWH. Because of the way the utility companies in Wyoming interpret and apply the net metering statute, they will not pay but half the retail price. And, yes rates are going up in Wyoming, about 12 c/KWH where I live. Some areas higher.
Thanks for your ideas and input, think I have this licked!