I have a Flex Fuel 60 that I installed fall of 2012. It has worked beautifully on both wood and pellets supplying heat and DHW for 5K sq ft house and shop. The unit quit working last week and at first inspection I believed the lambda (oxygen) sensor had failed. Once I had a chance to remove the sensor and do some testing, I have found that the sensor is working as designed, the boiler control is not supplying power to the o2 sensor heater circuit. Has anyone had problems with the control board on their Flex Fuel?