Hey everyone, thanks for having me on the forums here in advance. I know there are a TON of people on here who are seasoned pros with tons of great knowledge :)
A little bit about me, I've been a home-owner for almost 6 years and have recently purchased a different home, therefore am learning much about this home and its HVAC system. The home's original construction year is 1954 and there was an addition (large, almost equal to the old section of the house in size) constructed onto the house in the mid 1980s. I've been mechanically inclined my entire life and have worked on cars, built my parents' home with my dad and in general I'm good at electrical, mechanical, automotive, and even furnaces and garage heaters.
This house I've recently purchased (~2900 cumulative SqFt) has a VERY, very old Slant/Fin hydronic gas-fired boiler system installed in the basement, piped to the entirety of the house (not the attached garage). I contacted Slant/Fin and they stated the boiler's year of MFG is 1976, and it's a "Malibu" series, originally an oil-fired boiler. This thing was somehow retrofit converted to natural gas who-knows-when in the past. I paid a local HVAC company to do a basic inspection of the boiler and clean/test out the burners and combustion, and it's operating at 78% AFUE efficiency with 27 ppm CO emissions on combustion. It has a single Grundfos pump (unsure of size) circulating the entire system just upstream of the main return pipe at the boiler. The inspection stated the Grundfos pump and the expansion tank "are in like-new condition", and that the burner "operates decently".
I am really, really concerned about this thing. I would say that I have some decent DIY skill at HVAC now for forced air furnaces and garage heaters (I've installed a garage heater, wired and helped gas-plumb it), have done lots of maintenance work on my Goodman 96% 2-stage furnace at my previous house, BUT I have very very little experience with boilers at all, they're pretty foreign to me. I've been doing a TON of reading, video watching and learning and have done my best but I'm not sure what direction to take with this boiler. It's old, 44 YEARS OLD now! Will it fail on me in the middle of a Canadian winter? Winter gets down to -35/-40 degrees Celsius here (-37 F). Will this thing crap out on me in the middle of winter and destroy my pipes and the entire house?
What would you pros recommend? I had a quote from a local shop who had worked on this boiler for the former owner. He 'roughly' quoted me $ CAD ($ US) for a DIRECT-fit natural-draft replacement for a boiler installed, and $ CAD ($ US) for a condensing boiler installed. Could I buy a "similar" modern natural-draft Slant/Fin and install it myself? I have done plumbing with black iron, I'm VERY skilled at electrical and junction boxes/working with BX cable, etc, and have decent experience with HVAC like I wrote. I know I've read posts where you guys caution against a DIY guy doing this himself but I can't afford these INSANE quotes like this, not right now. I figure that I can buy a new boiler for approx $ CAD ($ US). Could I install it and then have a certified TSSA/journeyman come and properly connect the flue to the chimney, setup the gas burner, do tests of the boiler, all the loose-ends and sign off on my work? I feel like that's reasonable.
Thoughts??? Thank you guys in advance. Please help me before the winter hits. I'm unsure about this ancient Slant/Fin.
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