Step-by-step chimney flow check and spillage observation methods.
An open-flued appliance depends on its room air supply and a suitable flue route. Inspection, flue flow and spillage checks answer different questions; one satisfactory observation does not replace the others.
Flue flow: check the route
Before operating the appliance, complete the required visual and flue-flow checks. The flow check establishes whether smoke follows the intended chimney route and discharges correctly, without appearing where it should not. It is not, by itself, proof of the whole chimney's mechanical integrity or a substitute for any separate leakage test required by the procedure.
Spillage: check the running appliance
Where preliminary checks permit operation, follow the appliance instructions for its operating condition, warm-up period and smoke-test position. The spillage check assesses whether combustion products are being cleared instead of escaping into the room. There is no single five-minute routine or universal smoke position for every appliance.
Include the specified fan and door conditions. A pass with an extractor off does not cancel an unacceptable result with it running. Opening a window to obtain a pass does not establish that the installed permanent air supply is adequate.
Decide the action from the complete result
Only repeat a failed test where the applicable instructions allow that repeat and its conditions are met. Do not keep running a spilling appliance until a favourable result appears. Follow the current unsafe-situations procedure for classification and action, using the actual findings rather than assigning one label to every smoke observation.
Record the test conditions, result, defect and action. An appliance must not be left available for normal use with an unresolved unsafe flue or spillage condition.
Use this note to revise the decisions. Live test details come from the current standard, appliance instructions and competent gas-work procedure.
Something wrong, unclear or out of date? Report an issue with this note.