The owners of the house had gone away for a couple of weeks and were due to arrive home during the cold spell. As a welcome home surprise the nextdoor neighbour lit the boiler so that owners would not be cold when they arrived home. Unfortunately the pipes were frozen solid (and probably the pump) when he lit the boiler. As the heat had nowhere to go the boiler exploded setting the boiler room on fire.
The neighbours are still talking to each other.