I have a chance to get a boiler which is only 1.5 years old at a great price (maybe $700) and am seriously debating it. I have a 1-pipe steam system. And my current Weil-McLain boiler is at least 40 years old. It has a Riello F5 burner on it. I get my domestic hot water from it and use it as backup heat if we go away for Christmas. The existing boiler works, but due to some water issues we had in the basement (since corrected) it looks very rusty at its base, drains very slowly and the water is pretty rusty when I let a couple gallons of water off every other month. I'm wondering if I should just wait till this old beast dies (and leaves me w/o any hot water and a mess till I replace it) or be proactive and get this newer boiler now.
Also, I sized all my radiators and come up with 436 sq. ft. The boiler I'm looking at is a Thermaflo OSB-4, which puts out 450 sq. ft. and 144k btu. Before I got my coal stoker, I only ever used about 200 gallons of oil/month. So I don't think I'm under-sizing. But you guys are smarter than me.
I'd love to have a duel-fuel steam boiler in the basement, but my 6" chimney liner prevents getting a big boiler, since they have bigger flues. Even though my existing boiler has a 8" outlet, the installer reduced it to fit the 6" chimney liner.
I've also thought about getting a hot water heater, but my wife and I have 7 kids, and do mountains of laundry. We would need a huge hot water heater, and I only have 100 amp service, so don't really want to rev up my electric load. Which makes me want to keep using my boiler for hot water and backup heat, unless there is a better way. We can't get natural gas where we live so there are a lot of constraints to what we do.
What do you think?