This is the result of not calling a CORGI registered engineer to check your back boiler after others have worked on or around the flue. The original problem started a year before I was called when wasps had made a nest in the chimney pot and were using the house as a practice flying area. After calling the local councilĀ somebody showed up with a canister designed to poison the wasps. The home owner was then told to call a sweep to clean out the flue. Unfortunately, nobody told her to get the boiler checked to see if the fire was damaged or clogged. It was both!
The entire system was disconnect on the spot and the home owner was faced with a system replacement. Had they had the system checked after the flue was cleaned they would have discovered that soot, debris and hornets that had fallen into the heat exchanger and over a period of time caused it to block up fully.
Of course they were lucky – they could have gone to sleep and never woken up!
