Calculate mixed air temperature using outdoor air percentage or outdoor and return airflow in CFM, L/s or m³/h. Estimate outdoor air percentage from three temperatures.
Mixed air temperature is a weighted average of outdoor and return air. Enter an outdoor air percentage or both airflow quantities in CFM, L/s or m³/h. Use return air entering the mixing box, not total supply air. Volume weighting is an estimate that assumes similar air densities, no added heat and no condensation. Working backward from three temperatures helps check economizer operation, especially when outdoor and return temperatures differ by at least 10 to 20°F.
Estimates based on your inputs. Always verify against the manufacturer's data and the codes that apply where you work.
Describe the symptom and your readings. Brixon helps you work through the free, quick checks first, then the deeper tests. It can be wrong, so confirm on the equipment.
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