how do you drain a boiler?
You have to first make sure it is cool, Then open the vent or force the relief valve open. Then start opening the bottom blow line slowly and monitor boiler to ensure all water is drained. This is kind of a generic run through it really depends on application and boiler make and model. You also can wet layup a boiler also.
From the boiler draincock.
Draining a boiler is a good idea, however you should incorporate flushing of the boiler also. Often the water used in a boiler is not exactly clean and being from your house it certainly is not clean. During the constant heating and cooling of the water minerals and sediments will generally settle in the lowest points in the boiler; It is best if you flush out this combination because if left unchecked it will affect the amount of heating ability your boiler has which means you have to pay more money for your heating bill. Also it could affect the functioning of the low water trip which is a safety device built in to prevent boilers from firing up with too little water or no water in them, As said before, make sure the boiler is cool to the touch, the last thing you want to do is introduce cold water in a hot boiler as that could cause leaking and expensive repairs. The drain is generally at the lowest point in the boiler, perhaps attaching a garden hose to the drain and running the hose to a sump is the best bet, you have to keep that hose low because the boiler will not drain uphill. Drain and flush a couple of times until the water runs clear. Often on radiator steam heating boilers you do not have to vent,
