old Mansion heating renovation help

GW

Hi Guys,

I could use a bit of advice on this. This guy has this early 1900s small mansion (7000 sq ft.), and he currently is using the original heating system. The boiler look like they were swapped in the 50's or so, but it's 100% original other than that, even the expansion tank in the attic is still in operation.

As you see in the pics, there are rads in the extremities of the house (Servant's Quarters, and the 3rd floor), and outside air heat exchangers for the heart of the house, 5 of these HX units; zoned even with original compressed air by Johnson Control.

The owner desires 3 prices:

one to redo the boilers (about 900,000 BTU total). These are gas. Are there boilers that will work better than others for this, or should I modernize; get rid of the gravity and circ it? I'm not sure how the extra flow might affect the rads (orifices?) or the HXs

Secondy, he may want to revamp the entire heating system. Is it crazy to force warm air into these ducts? I could set up a bunch of AHU where the current units are now. We have a metal guy in house so this part we can handle. I realize I'll need some return air, as it is now there is either no return air (outside air is coming in, and heated air is leaving the house through at least one duct- OR, he can circulate air back to the basement... not good I'd say). With this method we could keep the old original cast iron grates in the floor.

Thirldy, he may want to add AC. I'm thinking a bunch of mini duct systems with a two or three chillers, and hydro air with new boilers. If it becomes option 3, I can make that happen, it's implimenting the old stuff that I'm not familiar with.

I'm going to give him some rough numbers for all the above and then charge him for some design work if he likes our ideas. He seems pretty cool for a mansion owner!

Thanks for any help-

Gary