Hello My name is Ian ~ I am not on the site constantly so please be patient whilst waiting for responses to you queries ~ can you let me have the full model number please?
There is no change in the water level in the tank. I have run the pump for over two minutes with no success (and no change in pump tone). I don't have locking levers, I have a knob ("security switch") which you set to "open" to remove the tank and "close" when you have replaced the tank. It is set to "close".
Running the pump for 2 minutes seems to have fixed it - water is coming through now. thanks.