Utica Boiler Ignition Problems

I have a natural gas fired Utica Boiler MGB 100 J Series II (heats water that is then circulated in baseboards for heat, 3 zones) installed in the fall of 2013. It worked great the first winter. On the second winter, it started having a series of error messages that showed up. (Very frequent 10 error messages, and on occasion a 62 error message.) I tried checking a couple of different things. Checked the gas pressure by certified person and the pressure was perfect. Then, we replaced the pilot assembly, and that worked for awhile. Later in the spring, the same errors messages showed up. We were past the warranty, of course, so tried installing a new circuit/motherboard on the boiler itself. This was not inexpensive. This seemed to worked for some time. This fall, the error messages are back and the boiler sometimes work, and sometimes does not work. A boiler that works on occasion when it is zero degrees out is not really an option. I had a 40 year old Burnham fuel oil boiler that was much more reliable than this boiler (not as efficient, and dirtier but at least it worked consistently). The damper works every time the boiler tries to start, there is a dedicated chimney for exhaust, etc. We had it inspected and when it does burn it burns very clean. (The person who inspected believes the natural gas in our area is on the drier side, which I understand is preferred to the wetter natural gas.) There is almost no carbon build up anywhere. I am at a loss and am hopeful that someone can help me get past the dreaded error messages so that we can have some heat.