I would like to thank everyone up front who is still around from back then for the wonderful support that was provided many years ago (and I helped back in areas of my expertise - and posted under the name "Perry" back then - not sure why I could not resurrect that name now). Also, to thank those providing similar support to people now.
After researching I installed a Vitodens 200 6-24 in my 1950's house with a cast iron baseboard monoflow T system; and I installed a transformer based surge protector (there are likely pictures in an old post if it still exists). Installed in October 2006; and I'm one of those guys where the gas company changed the meter because it had to be broke, and then wouldn't believe the new meter or my story until they inspected my new boiler.
A simple summary over the last 12.5 years is that since then it has performed well (once programmed right - I had to change the reset curve and enable hot water at night) as long as there were regular cleanings and drain trap/drain neutralizer maintenance, I missed cleaning one year and it failed due to a plugged boiler (which cleaned up). My fault!
One area of concern was that the fan started vibrating some years ago which started vibrating the cover - and progressively got worse. I could manage the cover vibrations by various means up to this winter when I just remove it.
I now have the 1st real failure: Code 04 which is Fan or the LGM 29 Card.
Last November along with the vibration I noticed that the ignition transformer tabs had broken (from the vibration and I taped it in approximate place suspended with electrical tape). I also ordered the replacement ignition transformer kit, and a new fan; but, did not install as the boiler was still running and it was a cold winter and the house and pipes could freeze if things went really wrong.
So today; after seeing the fault code and looking up that it was either the Fan or the LGM 29 card; I changed the Fan (cleaned everything up nice too, checked other things). I did not install the ignition transformer mod kit as I did not wish to complicate things at this stage (lets get the boiler running first). I know that most heating contractors cringe at homeowners doing their own work. Please hold your criticism for now: I was a skilled instrument and electronics technician before becoming an engineer; and there not a heating contractor in this area who has a clue about this boiler (not even the one who installed it - their one and only Viessmann on a T&M job for me); and we've paid professionals to stumble for 2 hours using the technical manuals I have in my house before they would agree to let me progress with what I know about the boiler - and then I solved the problem in about 30 minutes - and my wife still asks why we I even called them). I know the boiler. I know the programming. I am a technician, my work quality is high... and most of you would likely hire me as a technician if I could show you that I had any formal training in home heating systems and I wanted that kind of work (I can also solder copper pipe decently). I understand that I am the rare homeowner in this regard. But, we do exist.
Still Code 04 so its the LGM 29 card, and I'll have a cold house with no hot water until next week sometime (but it won't freeze now).
My question is should I also change the VR20 card at this time - just from a preventive maintenance standpoint (as I can be gone on trips during the winter). What is the history of circuit card longevity in boilers? Please provide your experience. Also, I've picked up some indications from other sources that the VR20 card fails more often than the LGM 29. What are the professionals who service the Vitodens seeing?
Also, here is the other reason I ask: Other than infant death, electronic circuits and circuit cards fail almost always for 2 reasons: Voltage surges which commonly kills transistors and shortens the life of many other components; and aging capacitors. I stopped the voltage surges from ever hitting the boiler up front. But capacitors age.
The typical life of a capacitor is 10-15 years unless specifically designed for long life using special long life capacitors (either large or costly - or both). Even if a circuit card sits in a box unused for 15 years... some of its capacitors may have degraded to the point that the circuit board will not work properly. Industries that run long life equipment (Power Plants, Metal Mills, etc) all have programs that systematically replace capacitors on many circuit boards because there are no real advantages in replacing the older control systems (and the modern ones also have the capacitor aging issue).
Now it is possible that Viessmann did design for very high capacitor life... It's also that I got a good life out of one of my original control cards. That is why I was asking about your folks experience with circuit board life in boilers..
Thanks for your patience in my writing a longer post than necessary to just as the base question. I thought you would like the background.