Pressure problems with Vaillant Turbomax Plus 824?

The pressure reading on our Vaillant Turbomax Plus 824 is reading above 3 bar when the central heating is swithced on. There is also warm water dripping constantly from the outlet pipe. The boiler was serviced back in July 10 and the gas engineer advised us that he thought the heat exchanger was faulty and that we would have to replace the boiler at some point in the near futrure. The boiler was installed in 2003. Taking the above information in to consideration can the fault be corrected or will we need to install a new boiler?