Check the full flue route, correct terminal and leakage before the appliance’s operating spillage test.
A flue-flow check examines whether the flue provides an effective route to the correct terminal without leakage into the building or adjoining premises. It is carried out before the appliance is put into operation for the spillage test.
Check the complete route
Inspect the flue and follow the prescribed preparation, smoke source and test position. The procedure determines whether any preparation or warming of the flue is needed; “the appliance is not firing” does not mean every test must use an unprepared cold flue.
Check where the smoke goes. It should discharge from the correct terminal. Check for smoke leakage along the route, including into rooms, roofspaces, voids or adjoining property, and assess any leakage against the applicable test method. Seeing smoke at the top alone is not proof that the rest of the route is sound. Smoke at the wrong terminal, a downdraught, no flow or unacceptable leakage is an unsatisfactory finding.
Keep the two tests separate
Once the flue-flow check is satisfactory, an operating spillage test checks whether the connected appliance clears its combustion products under the specified appliance, room and fan conditions. Passing either check does not replace the other or the remaining safety checks.
Treat a failed flue-flow check as a stop. Investigate and rectify the cause, then repeat the required checks before operating the appliance. Fitting a liner or clearing a blockage does not remove the need to verify the completed flue.
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