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possible conversion from 16 zone, 2 buderus g115 boiler to Lochnivar Knight - good idea?
A few years ago, you guys helped me with some issues with my existing system. I am now thinking about changing it out, but I don't know if a low mass, condensing gas boilers is a good fit for my large system.
The system consists of 2 G115's with a 2017 logmatic control with the dual burner module installed. There are about 6 non mixed hot water baseboard/runtal radiator zones and about 10 mixed radiant floor zones. there also is 1 coil in an airhandler. They radiant zone manifold iscontrolled by a taco injector pump (can't remember the model number) but it has temp sensors strapped to the radiant side to control the amount of hot water injected. Every zone has a dedicated circulator and there is also a main system pump. There also is a 110 gall buderus domestic hot water tank .
All thermostats are tied into a home automation system so we have full temperature setback control in each room from the automation system. I am not using logmatic for any type of temp setback but we do use the outdoor reset.
total btu is about 240k, but it actually a little undersized. There were some additions put on this house and we relied on not all 16 zones running at the same time. So heating has been no problem, even in last year's bad winter. Based on the heat gain/loss, a 285k unit would be perfect.
given the fact that we have 16 circulator pumps and 1 system pump, I am not sure if a low mass modulating boiler is correct. I know they are sensitive to gpm flow, and with all zones active ( a rarity) I don't know if that much water flowing through works. In the past, i've relied on my local HVAC contractors, but this "old school" area still believes in massive, oversized, cast iron boilers.
I'd love to have 1 boiler that I can monitor via pc (which is why I like the knight.) But I know just enough to be dangerous. thoughts on a low mass boiler for something like this? My (possibly incorrect) thinking is that when only 1 zone is calling, the boiler can run at 20%, etc. So the modulating idea is appealing.