caravan boiler 2003 worcester no pressure or water?

The boiler was installed into the caravan back in 2003. When arriving at the caravan for the first time this season I cannot fill the radiators or the boiler system with water. All the taps are turned on as the water is flowing from all the sink taps. Toilet system has filled up nicely but nothing else. Also the pressure on the boiler is zero. There is no key and no place for the key to fit into allowing us to put pressure back into the boiler. Found the reset button which ignited the piolt. The pump is working but cannot fill the boiler with water??????? please help. Looked under the caravan for any additional taps but to no avail..