Boiler Reference

Per-model service-mode steps & expected combustion readings.
Always double-check readings against the appliance's own manual and data badge before relying on them on site.

Gas rate calculator

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1:00Start when you take the first reading
Gas used
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Gas rate
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Heat input gross
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Heat input net
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Run the appliance at maximum for the test, with all other gas appliances off. Metric: note the meter reading, time exactly 1 minute, note it again. Net = gross ÷ 1.11. Calculated with a calorific value of 38.76 MJ/m³.