We did some work for a regular selling their home. Most of the system is original:
Here's Mr. Boiler. Said Crane Basmore on it, always gas. 570K input. Homeowner put on his instructions to the new owner that it was 88% efficient. Hmmm. Stays hot based on aquastat. Heats the house via a fan coil and ducts plus cast iron radiators in recessed in the wall. Oh, and a little infloor by the front door.
When the buyer was checking things out with our tech, this pump fried. Ended up replacing with a Taco 0010 at their suggestion. Didn't run it long enough to see what it would do, didn't want to heat up the house on a steamy day. This pump moved water through the air handler coil.
At least the ancient isolating valves held!
And then tried to fire this one, which serves the radiation. Nothing. Still had the plans from 1942 and tried to trace. I finally started playing with the ancient stat and it kicked in. The tech cleaned the stat contacts and cycled OK after that.
This little condensing unit in the boiler room serves a walk in cooler in another part of the basement. The HO didn't know why it didn't work. Originally the compressor and water cooled condenser for the central air was down there but it had long been replaced with conventional outdoor unit and A coil.
Even with the wiring diagram, took some doing to figure this out. And on another wall are even more switches and disconnects. On the air handler, there's a summer-winter switch. Summer turns on the blower constantly and a motor moves the dampers to push air around the heating coil. Winter turns off the blower and the dampers move to allow air through the heating coil. On the wall is a switch to keep the outdoor unit from coming on - it runs by a line voltage stat in the 2nd floor bedroom. After going to winter and turning off the cooling, the screwdriver to adjust the aquastat is on one of those disconnects. They would turn the water temp up. 2 stats on the main floor controlled heat. One for the air handler, one for the radiators.
Check out this beauty. 13' long, just under 6' high and 6' wide. 3/4 hp belt drive motor. Doors for service. First is access to filters (now) and the black box on the side of the AH was HUGE capacitors for the electronic cells that were no longer used. They looked just like a gigantic version of a F300! Middle door (oh, see the light switches for each compartment) was for hot water coil and closest door for blower motor. A coil for 4 ton A/C is on outlet of air handler. We have an Allegiance 12 outdoor unit on it.
This is a scan from a 1955 brochure showing the heating stats. Said TA147A1C4X on them, no date code. So could be original or changed later. Clocks didn't work.
Steelersfan, these are down your way in Meridian Kessler.