I recently built a new airing cupboard and I had to drain down the central heating, construct the cupboard and then reconnect everything. So far so, good. Filled the system up with water, switched on the pump. Shortly afterwards the radiators were bled and they all heated up nicely.
Problem is that although the radiators were hot the cylinder is cold as are the pipes feeding it.
Also, there is no hot water unless you use the Immersion heater and when you use this there is a large portion of the cylinder (the bottom part) that remains cold.
It seems as if there is a huge airlock of some description.
Any suggestions to remove it, that is if it is an airlock.