Hello, I'm looking to zone out and/or replace our 1950s single zone monoflow system and looking for some advice.
The house is a 1950s ranch, about 2000 square feet first floor and almost the same in an unfinished basement. The old boiler ~250k original boiler was replaced with a Lennox 100k BTU (80% efficiency) a year and a half ago by a local contractor, not terribly pleased with their work (it was ok, but not great) and their service department has been really nasty, so 'm not really tied to them. It's a dual 1.5" pipe around the house to 14 sunrad radiators on the first floor. Eventually we will add 6-7 CI radiators in the basement.
Total EDR for the first floor is 600. At 180* that's 102K BTU, my calculation for the first floor requirements is something like 35K. I'd like to split the first floor into 3 zones (bedroom, living area/kitchen, and room above gararge).
Problems to solve:
Monoflow 1.5" pipe heats unevenly, hangs down into space we're going to build into
no bypass loop on boiler, so for 30 minutes or more it's getting cold return water, water is condensing on outside of jacket.
Radiation is way over sized for our house needs. We insulated to R40 in the attic, all new windows, air sealing etc...
Need new zone in the basement at a minimum
Not reasonable to run homeruns to every radiator, new basement walls will hold new pex lines ideally.
lennox gwb-100e boiler not sure as to it's capabilities, seems to be a simple integrated high temp cut off, can not be replaced.
My wife and I bought the house about 2 years ago and basically have replaced almost everything ourselves, plumbing, electric, drywall, tile with permits which just passed final inspection. The boiler, central air, siding/roof was done by contractors.
My thought is to do a reverse return system with 4 zone valves, bypasss diverter, maybe a smart circulator. What I would like, is to hack apart the monoflow main line and run the pex dual lines myself back to the boiler and then have a good professional plumb/wire all that up for me. I'm proficient at sweating joints and pex, but I don't have enough knowledge to plan this out completely. I've gone through 2 boiler replacements (2 different houses) and it's always a let down at the end. Once the guy plumbed the compression tank in a useless place, this time there is no bypass boiler loop or dielectric union so the boiler is corroding after only 2 seasons.
Am I on the right track? I've done all the heat loss calculations for all the rooms, and the EDR calculations for my existing radiators, and need some direction on where to go with the planning. I'd like to find a contractor who'd work with me on doing part as well.