My house has a radiant heating boiler system which I will be removing. I am beginning to drain the system and disassemble the unit. Since this is a continuous system with three zones, there are no release valves anywhere throughout the piping. Therefore, I wanted to ensure the proper method for draining.
On the side of the boiler is a spigot which I know is the main draining point. Though, I question the spigots located on three separate pipes, which I assume is for each zone. Do I need to drain from them as well? Due to suction/pressure in the system, I would think there may still be water even after I drain the main spigot. Therefore, it appears logical to also drain from the other three spigots.
Appreciate any help.
Here are photos of the spigots.
Main spigot on side of boiler >>>>