Boy I don't get it.Our 165 has been workin fine with no mods but an elbow on the vent to keep it from steamin, and some extra chimney height..Bought two extra therm-o-disc thermostats just in case-they're still sitting on the shelf..blower's been working fine,just close the shutter a little during a warm spell..maybe set the temp down a hair..it maintains an almost constant 170-190 temp to the house...using a re-circ pump for the DHW seemed to help too..DHW is better than what the oil burner provided..and free...as for the chimney sweating under the roof,I don't know..been looking for it but nothing yet....could be a poorly sealed coil cover causing it...Just my 2 cents---J
I am happy with my 165 when its above 0 degrees outside it works fine. When it gets -25 and windy the furnace can't make enough heat and I think the main reason is it's not insulated good enough. The entire bottom of the water jacket exposed to -25? And a lesser complaint is the uninsulated door.
The lack of insulation underneath in a way isn't that big a deal insomuch is that's something I can fix myself (now that I am even aware of it, I wouldn't have even known about it if I read it in this or another forum)
I will know next winter if I will be able to recommend it to anyone or not, if insulating it helps as much as I am hoping it will I would probably still recommend it to someone who is a little bit handy