1st, turn the boiler off and do NOT use it!
The condence on any boiler is an integral part of the flue system. Melted traps also have a tendancy to be only a short way from being on fire...
I wont divulge information to the causes of this problem as it is too serious to attempt a repair yourself.
I fully recommend getting an OFTEC engineer around pronto. Also, if you are not registered, you should have applied for your local building control officer to come and inspect the installation and then have an OFTEC engineer to commission the installation....
Oil Only, October 2010