Sealed system

[JakeAdlard]

Is it safe to drain the house to fix a badly leaking tap with a sealed system, I'm very ignorant to a sealed system and more used to the cold water cistern in loft, the only stopcock I can find is in the front garden, I was just wondering if it would effect central heating etc, I'm not a plumber so any advice would be helpful

 

[phishfood]

Are the domestic hot (hot water to the showers, taps, clothes laundry, etc) and central heating systems all one system, or two separate systems?

Either way, the central heating system should have a provisions for flushing the air, but without looking at it, I couldn't tell you where.