On Wed, 9 May 2018 20:45:38 -0600, lowbrowman, the endlessly driveling
senile idiot, blabbered again:


One picture... It's steam, not hot water. The steam flows to the
radiator and the condensate returns to the boiler. When the boiler shuts
down the system fills with air. The air has to be bled to allow the
steam to reach the radiator, hence the air vent. In theory when the air
is all vented the valve shuts off; in practice the damn things can
whistle like a tea kettle.

That was a very nice explanation, lowbrowman! You may suck his cock now
again, cocksucker!