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The water cannot originate from the primary chilled-water system for the building, but must be supplied as
part of a secondary closed-loop system.
Important: Do not use glycol solutions, because they can adversely affect the cooling performance of the
heat exchanger.
Materials to use in secondary loops
Use any of the following materials in supply lines, connectors, manifolds, pumps and any other hardware that
makes up the closed-loop water-supply system:
• Copper
• Brass with less than 30% zinc content
• Stainless steel 303 or 316
• Peroxidecured ethylene propylene diene monomer (EPDM) rubber, non-metal-oxide material
Materials to avoid in secondary loops
Do not use any of the following materials in any part of the water-supply system:
• Oxidizing biocides, such as chlorine, bromine, and chlorine dioxide
• Aluminum
• Brass with greater than 30% zinc
• Irons (non-stainless steel)
Water-supply requirements for secondary loops
This section includes specific characteristics of the system that supplies the chilled conditioned water to the
heat exchanger.
• Temperature:
The heat exchanger and its supply hose and return hoses are not insulated. Avoid any condition that might
cause condensation. The temperature of the water inside the supply hose, return hose, and heat
exchanger must be kept above the dew point of the location where the heat exchanger is being used.
Attention: Typical primary chilled water is too cold for use in this application because building chilled
water can be as cold as 4°C - 6°C (39°F - 43°F).
Important: The system that supplies the cooling water must be able to measure the room dew point and
automatically adjust the water temperature accordingly. Otherwise, the water temperature must be above
the maximum dew point for that data center installation. For example, the following minimum water
temperature must be maintained:
– 18°C ±1°C (64.4°F ±1.8°F). This is applicable within an ASHRAE Class 1 Environmental Specification
that requires a maximum dew point of 17°C (62.6°F).
– 22°C ±1°C (71.6°F ±1.8°F). This is applicable within an ASHRAE Class 2 Environmental Specification
that requires a maximum dew point of 21°C (69.8°F).
See the ASHRAE document Thermal Guidelines for Data Processing Environments. Information about
obtaining this document is at https://www.techstreet.com/ashrae/products/1909403.
• Pressure
The water pressure in the secondary loop must be less than 690 kPa (100 psi). Normal operating pressure
at the heat exchanger must be 414 kPa (60 psi) or less.
• Flow rate
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ThinkSystem Heavy Duty Full Depth 48U Rack Cabinet User Guide
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