Draining the hot water pipes: plumbing in sink

When I plumb in the new kitchen sink I am expecting that after I turn off the water at the stop tap the water in the 'hot' pipes will take ages to run off [because of what is in the immersion heater] - am I right?

I haven't had a conventional boiler system before......

If u only isolate the cold water stop tap it will take a while 4 the hot to stop as u will be draining the cold water storage tank for the cylinder. There should be a red headed gate valve on the pipe out of the cold water storage tank the feeds in to the bottom of the cylinder, If closed this will remove the need to drain the water tank & reduce the risk of air locks when refilling.

Thanks for your help - I have located the red valve and it all makes more sense now...cheers