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Cisco Wide Area Virtualization Engine 594 and 694 Hardware Installation Guide
OL-24619-02
Appendix B Maintaining the WAVE-594 and WAVE-694
Maintaining Your Site Environment
Temperature
Temperature extremes can cause a variety of problems, including premature aging and failure of chips
or mechanical failure of appliances. Extreme temperature fluctuations can cause chips to become loose
in their sockets and can cause expansion and contraction of disk drive platters, resulting in read or write
data errors.
To minimize the negative effects of the temperature on system performance, follow these guidelines:
• Ensure that the system is operated in an environment that does not exceed 0 to 40ºC (32 to 104ºF)
in either direction. The upper end of operating temperature above applies up to an altitude of 1,000
meters (3,281 feet) and then subtract 3ºC for each additional 1,000 meters up to a maximum
operational altitude of 3,000 meters (9,843 feet).
• Ensure that the system has adequate ventilation. Do not place it within a closed-in wall unit or on
top of cloth, which can act as insulation. Do not place it where it will receive direct sunlight,
particularly in the afternoon. Do not place it next to a heat source of any kind, including heating
vents during winter.
Adequate ventilation is particularly important at high altitudes. System performance may not be
optimum when the system is operating at high temperatures as well as high altitudes.
• Make sure that all slots and openings on the system remain unobstructed,
especially the fan vent on the back of the system.
• Clean the system at regular intervals to avoid any buildup of dust and debris, which can cause a
system to overheat.
• If the system has been exposed to abnormally cold temperatures, allow a 2-hour warm-up period to
bring it up to a normal operating temperature before turning it on. Failure to do so may cause damage
to internal components, particularly the hard disk drives.
• If intermittent system failures are noticed, try reseating any socketed chips, which might have
become loose because of temperature fluctuations.
Humidity
High-humidity conditions can cause moisture migration and penetration into the system. This moisture
can cause corrosion of internal components and degradation of properties such as electrical resistance
and thermal conductivity. Extreme moisture buildup inside the system can result in electrical shorts,
which can cause serious damage to the system.
Each system is rated to operate at 10 to 90 percent non-condensing relative humidity. Buildings in which
climate is controlled by air conditioning in the warmer months and by heat during the colder months
usually maintain an acceptable level of humidity for system equipment. However, if a system is located
in an unusually humid location, a dehumidifier can be used to maintain the humidity within an
acceptable range.
Altitude
Operating a system at high altitude (low pressure) reduces the efficiency of forced and convection
cooling and can result in electrical problems related to arcing and corona effects. This condition can also
cause sealed components with internal pressure, such as electrolytic capacitors, to fail or perform at
reduced efficiency.