This part of ISO 9459 establishes test procedures for characterizing the Performance of solar domestic water heating Systems operated without auxiliary boosting, and for predicting annual Performance in any given climatic and operating conditions, but only for an evening draw-off. A “black box” approach is adopted which involves no assumptions about the type of System under test; the procedures are therefore suitable for testing all types of Systems, including forced circulation, thermosiphon, freon-charged and integrated collector-storage Systems. This part of ISO 9459 is not intended to be used for testing solar heating Systems which have an auxiliary heater as an integral patt of the System, since the Operation of the auxiliary input may influence the Performance of the solar heating System. To quantify the interaction between the energy inputs, the test procedure described in ISO 9459-3 is recommended. This part of ISO 9459 applies to solar-only domestic water heating Systems designed to heat potable water to be supplied for domestic water usage and is not intended to be applied to other Systems. The test procedures are applicable only to Systems of 0,6 m3 of solar storage capacity or less. The test procedures in this part of ISO 9459 do not require the solar water heating System to be subjected to freezing conditions. Consequently, the energy consumed or lost by a System while operating in the freezeprotection mode is not determined. This part of ISO 9459 is not generally applicable to concentrating Systems. lt is not intended to be used for testing the individual components of the System, nor is it intended to abridge any safety or health requirements.