Best Of

No dust collection is that good. Forget forced air unless a seriously oversized filter system is installed.

In floor radiant

Hot water coils with drains so the coils can be washed periodically.

How close is your indirect circ to the air separator? I've seen them pull in air when piped too close.

If you really want to get good feedback you may share a few more specifics, like what specifically are you doing with the building? you say a business but what type of business, factory, office, art gallery, retail etc. How many employees? what climate zone? Occupied hours? Are there going to be any large machines in the space? are you processing wood and creating a ton of combustible sawdust? rough sketch of the building as you suppose it will be once finished, general layout and what each space will be used for. Also keep in mind that depending on your jurisdiction you may be required to get an engineer to stamp your mechanical design, and possibly other plans as well, but no harm in seeking advice before committing to an engineered design.

The EG-75 has an input of 282K BTUH. This is sufficient to heat a small apartment building (I have done it with less). It absolutely requires 3" risers and a minimum of a 4" header………………one could make a good argument for a 5" header.

You have none of that.

Instead of doing the right thing and determining exactly what size boiler you require based upon the radiation, you install a giant EG-75 with totally improper near boiler piping (in copper !!) by unqualified idiots and you expect it to actually work.

Good luck with that.

First step before any brands is to figure out how big of a boiler you actually need. If you are not using about 5000therms of natural gas in a heating season, it is not 200kBTU.

You can take a gas bill from last winter and run through the math here to figure out what you actually need:

https://www.greenbuildingadvisor.com/article/replacing-a-furnace-or-boiler

With cast iron rads the oversizing is not so much an issue but you are paying for more equipment than you need.

With older houses and mass rads, you also want outdoor reset with constant circulation, make sure the installer sets it up. Besides the fuel savings, this keeps the rads at a more even temperature which is good for comfort plus it also stops any banging from pipe expansion.