Thermo Scientific 180 Series, Руководство по эксплуатации и техническому обслуживанию

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Section 6
Maintenance
Warning Unit must be disconnected from power source prior to servicing.
It is recommended that all service be performed by qualified service
personnel.
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Caution Electrolysis can damage stainless steel. This can occur if an object
is allowed to rest directly on the surface, trapping moisture that becomes
oxygen starved but is surrounded by water containing oxygen. The
resulting electrolytic action will pit or corrode the stainless steel.
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Stainless steel is an alloy of steel with chromium and nickel which increase
the metal's resistance to rust and corrosion. However, if not properly cared
for it can rust and corrode. Exposure to air provides the passivations for
clean stainless steel. This exposure produces a thin, durable chromium-
oxide film that forms rapidly on the alloy surface and gives stainless steel
its characteristic "stainless" quality. Exposure of the surface to water other
oxidizing environments also produces this passivating film. However, if
free oxygen is not available due to scale or contamination buildup, the
metal surface may become vulnerable to attack.
Maintaining a neutral pH and frequent cleaning with detergent and water
will give you years of trouble-free service for your water bath. The
following are some guidelines to keep in mind.
Distilled water is recommended. Maintain pH between 7 and 9 to
minimize corrosion of the stainless steel.
De-ionized or reverse-osmosis water may be used. However, if this water
is very pure, it may be corrosive to stainless steel; and
in such cases always
add 20-40 ppm (20 to 40 mg/liter) disodium phosphate or sodium
bicarbonate. Adjust dosage to give a pH of 7 to 9. See "pH Control"
below.
If the above water is not available, clean, aerated soft tap water may be
used, provided the total solids concentration is <500 ppm.
GP Water Baths 6-1 Thermo Scientific
Background
Water