CRCasey-- thanks for the hand!
(Edited after progress)
So, I have the thing taken apart completely and most parts soaking in a citric solution. Will post pics soon, but haven't had the chance to create a flickr account or something of the sort.
Anyhow-- after some feedback I have a feeling that there's an issue with the solenoid that feeds the boiler / heat exchanger. (Pic below)
I haven't gotten to dealing with it yet nor am I sure if it's a problem (haven't tried running it since first acquired), but want to make sure that I can reach / access everything before putting the whole gig back together...
Is it worth taking the thing apart and figuring out the details or should I just go for a new one? If answer is new one, can you point me in the right direction? I've looked through some websites but can't seem to find the right one. Mine seems to be made by honeywell?

thanks!
oren