Smoke testing

Check new chimneys for blockage and soundness before use.

Gently lower a coring ball through the flue to determine that it is free from blockage, as for clearing fresh mortar from the bore.

Use a smoke test to check for leakage.

With chimney systems the chimney must be tested before the expansion plate is fitted.

Close up any fitted appliance. Warm the chimney flue for about ten minutes using a blowlamp or similar heating device.

Put two smoke pellets in the appliance firebox (or bottom of the chimney or the appliance recess) and light.

Close the appliance when smoke is formed and allow the smoke to make its way up the chimney. If an open fire is fitted or if the recess is empty, seal the recess using a piece of board sealed at the edges. When smoke is visible from the terminal, seal it, using an inflatable plug or polythene bag.

Remember to remove the seal after the test.

Check for leakage throughout the length of the chimney by examining the chimneybreasts and adjacent walls. Leakage may occur at some distance from a fault. Pay particular attention to barge overhangs and eaves to see leakage through wall cavities.