Can you open and close valves? Turn the boiler switch off. Close the
feed
to the system. Find the drain valve, usually on the return line of the
loop
and drain the water. Do your work, close the drain, open the fill. Once
it
stops running, you'll have to turn the heater on, run the system and crack
open the drain valve to vent some of the air.


I'll do a search on opening and closing valves.... (just kidding)
I would think its as simple as you say but I've never done it and I'm
covering my bases.
Still a little cold to have no heat if I run into a problem getting things
back up and running.

The furnace is in a crawl space so I don't see it that often.. I'll crawl in
and hopefully the correct valves will be apparent.


Thanks

Steve