Rheem Solar Hiline Water Heater Owner's Manual And Installation Instructions page 12

REGULAR CARE
FLUSHING THE SOLAR COLLECTORS
It may be necessary to flush the solar collectors if there is sediment in the water supply. This should be
conducted by a person qualified to do so and in the morning within three hours of sunrise, when the water
temperature inside the solar collector(s) is lower.
Warning: Care must be exercised to avoid splashing of water, as water discharged from the solar
collector(s) and solar storage tank may be of a very high temperature.
It is recommended to have the solar collectors flushed every five years. This will assist in keeping the solar
collectors, solar cold pipe and solar hot pipe clear of sediment.
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