Vokera Linea 32HE Combi Boiler

I have had the above boiler for approximately 30 months now and have been delighted with the performance.However i noticed last night a drip coming from within the casing.The pressure was up to 2.5 bar from around about what i normally have it at 1.5-1.7 bar.
I have a one inch pipe draining the condensed water on an outside north facing wall.Because of the cold weather i noticed a build up of frozen water inside the pipe and after some warm water was applied to the pipe a large amount of water and ice came out .
Can anyone explain if this would cause this problem to happen as i'm sure i won't be the first to encounter this .i.e would a blocked/frozen pipe bring about these symptoms.
Getting hold of a gas engineer at this time seems near impossible.

sounds like two issues.

your condensate pipe was frozen and the backed up condensate will often find its way out another way.

the high pressure could indicate the expansion vessel is flat. being slightly higher than normal this pressure could also be forcing system water past a dodgy seal and giving you a small leak.

checked for frozen condensate pipe and it appeared to have been the problem as this was filled with frozen water.defrosted it and hey presto cured the problem.first time i have encountered this problem although its the first condensing combi i have owned.spoke to british gas fitter who said he was inundated with condensing pipes freezin due to extremely low temperatures