I wanted to add a few rads to my system so after shutting off both sides of all rads and cold water supply I drained the system using a drain valve from downstairs. Anyway to cut a long story short it took ages to drain with what seemed like way to much water, after it finished I went to wash my hands and low and behold I had no hot water in the tank. Now I'm really confused as to why the domestic hot water tank should have emptied when I was draining my gravity fed CH using a drain valve off a rad. Can anyone enlighten me as to why this should happen and does it mean (not getting any sludge through my domestic hot water so doubt its mixing) that somehow my CH water is mixing with my domestic supply?
Steve
Steve