what is the pupose of a boiler drain?
ITS THE DRAIN IN CASE THE PRESSURE RELIEF VALVE GOES
It's there to let you drain off some of the sediment debris from time to time. Not too often as it's best not to introduce new water - with the accompanying new minerals - into the system.
A boiler drain is just that, A drain. It's for draining, say a water heater, so you can replace the unit. Hose bibs on a house are also used as drains by plumbers who are going to be doing work on piping inside the house.
