How many inspectors come across these old systems still?
Here’s a couple of tips if you do.
Don’t operate the bleed valves!
If they work great you will get to see black rusty water spit our everwhere, or hear air escaping from a system that needs bleeding. But these have a nasty tendency of breaking or stripping the threads. You will be left with a real problem or having to shut-off the water feed, turning off the heating and paying for a plumber to come and repair the valve, which could require re-tapping the radiator. Not cheap. Operating the bleed valves is NOT part of an inspection scope. They are NOT considered normal operating controls and are there for maintenance of the system.
Don’t operate the main radiator valve!
It’s not a shut-off valve. It’s designed to assist in the balancing of a system. These are rarely completely open or completely closed. They are set to ensure all radiators in the system get the same flow of water to provide even heat around the home. Older valaves have been set in their position for so long, moving then can beak the seal or create a leak. You will be responsible for that leak, and damage it causes and any repairs. The repairs in this case will be way more expensive than a bleed valve leak, because even shutting off the water inlet to the system you will have whatever water is in the system at a higher level to drain out of the leak and there is nothing you can do, unless you drain the system yourself.
Only operate the Hydronic heating via the same thermostatic controls you would do for forced air.
You have been warned.