HVACopediaSuperheat (fixed orifice / cap tube)
Actual superheat and the target from the outdoor and indoor temperatures.
Good to know
- This check is for fixed-orifice and cap-tube systems. For a TXV system use the subcooling check instead.
- The target is read from a chart for typical residential cooling. The manufacturer's own chart on the unit always comes first.
More refrigeration calculators
Subcooling (TXV systems)Subcooling from the head pressure and the liquid line tempRecovery cylinder max fillThe 80% rule: how much refrigerant a cylinder may holdVacuum pump sizePump size and vacuum targets by system sizeVacuum decay testLeak or moisture? Read the micron rise after isolating the pumpWalk-in cooler / freezer loadWall, door-air, product and extra heat loads; suggested capacityDefrost heater energykWh and heat added per day from the defrost cycles
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Calculation aids and reference figures for licensed technicians. Always follow the manufacturer’s data plate and manual for the exact model, and local codes. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Pressures are typical saturation values and change with load and airflow.