Initially, the flue should be warmed. This is to establish a draught. Draught is a result of pressure differentials – the air inside the flue being warmer than the air outside, and therefore lighter. This causes the air to rise – or be ‘pulled’ out from the chimney.
Once the chimney is heated sufficiently to achieve a good draught, the windows and doors to the room should be closed. A smoke pellet (capable of producing 24 cubic meters of smoke in a minute) should then be placed in the fireplace opening or appliance to establish that the smoke safely escapes the room via the chimne, with no spillage. Once this has been established, our engineer will venture outside to witness the smoke ‘evacuating’ the chimney pot, or terminal. We will then visually inspect the chimney stack, roof, flashing, adjacent pots and general chimney structure to ensure there is no visible leakage, or any obvious reason for concern.
If the smoke clears the room and exits the chimney without fault, the test will be passed. If it spills into the room or leaks somewhere it shouldn’t, the problem will be inspected more thoroughly before a resolution is suggested.