Back in the UK, I had a Calor Gas fuelled condenser boiler for hot water and central heating.
I came here for 3 months in November 2012, returning there in January 2013. My home was in a frost pocket where the sun didn't shine between November and February as the hills surrounding the valley were taller than the sun's zenith at that time of year. I'd set the central heating to operate when outside temperatures fell towards 0C, just to prevent the system freezing - or so I thought... Instead, the boiler would fire up, and condensation would form in the ventilation pipe that led from the boiler through the kitchen wall some 2 metres away. It dripped outside the house, and when temperatures were below freezing, an icicle would form. A few days of this would see the icicle develop into a plug that blocked the pipe. Once the pipe filled with water behind the plug, a safety cut-out shut off the system until the water dissipated - which it didn't in the frost, which led to the temperature within the house falling lower and lower. Inevitably, a pipe burst, and I was greeted with a ruined kitchen, with carpets in the adjoining dining room and lounge left wet through... I enjoyed a few nights in a local hotel until the damage could be fixed - which included removal of the very long "plug."
I doubt that I will ever buy another condenser boiler!