Drain Valve Location
In order to drain your boiler, you will first need to know what a boiler drain valve is and where to locate it on your boiler. Not all boilers may look the same, but typically, you will find the drain valve near the base of the boiler, almost always at the boiler's lowest point.
Valve Physical Characteristics
Look for a valve screwed onto a short, threaded pipe protruding from your boiler. Most likely it will be the only one protruding from the boiler that does not connect to another pipe. On the outside end of the drain valve you'll see a spigot, similar to one you'd see on a faucet.