I'm trying to install a replacement shower pump. To do so, because there are no isolation valves on the inlet pipes, I believe I have to a) empty the cold water tank in the loft, and b) empty the hot water cylinder. I've drained off the loft tank OK, and have tied up the ball valves so it doesn't refill. Now, however, I can't drain off the hot water - the hot water taps run for a very short while then stop. I was puzzled about this, so I untied the ball valves in the loft tank to allow water into the header tank, and sure enough the hot water started flowing again. Why is this? Air lock?
So, how do I achieve what I need to achieve, namely to shut off both hot and cold water feeds to the shower pump?
So, how do I achieve what I need to achieve, namely to shut off both hot and cold water feeds to the shower pump?