Air Locked Hot Water Cylinder

I have what appears to be an air locked hot water cylinder. Non of the hot water taps are working. It happens after a water cut and the hot cylinder got emptied.

Any suggestions on how to clear the air lock.

I lived in an old house with piping a bit humpy and when ever the system was drained I would have an airlock in the hot water supply. The following procedure cured the problem - much to my surprise. Use a short loop of heavy duty rubber tubing to connect the cold water rising mains tap to the hot tap. The kitchen sink is the place to do this. Open the hot tap and then the cold tap . The mains pressure will force the water back up the piping to the header tank eliminating the air lock. This worked for me - it may not be suitable in modern pressurised plumbing systems.