Re hot water boiler heating system,with 3 zone valves,in home.need to know to know about small "automatic"? Vents at ends of rads One was 'leaking']slowly but steadilty.and dripping slowly thro to basement forming small 3 inch mark on floor. 4 years ago these "automatic" valves replaced (from round knob turn type ) by professional. I did press on the small pin like
Thing in centre and water spurted. I cleaned up the water and then screwed the cap on tightly.
Is the cap supposed to be on tightly ? If "automatic' need they be bled
Would appreciate advice

sheplumb

I managed an apartment that had radiators and used steam for heat...

They had relief valves on one end and seemed a little messy, the system

Would cool down and water would return to the boiler... The heat would

Come on in the morning and the relief valves would spit and sputter

Until the system was hot, had many compliments on how good heat was...

Had to fix relief valves in many apartments to get the heat...

Maybe there is a way to catch leak, and not interfere with operation

There are craft thingies on the internet, maybe they have ideas...

There are likely people here that can give a good answer if you give them time.

I am bleeding today too. One of my bleeders is that type and you have to leave the slightly loose.