Hypertherm HT4400 HySpeed Plasma Arc Cutting System - Manual (Page 38)

INSTALLATION
3-4 HT4400 Instruction Manual
7
Water Purity Requirements for Coolant Mixture
Maintaining a low level of calcium carbonate is critical for proper performance of the torch and components in the
cooling system. Water purity should meet the requirements defined in the table below. When mixing Hypertherm
coolant (P/N 028873 - 100% propylene glycol) with water to create the appropriate coolant mixture.
Note: If water purity exceeds maximum levels, mineral deposits may occur throughout the system.
If water purity is below minimum levels, soluble materials may leach into the coolant.
Water Purity Measurement Methods
Conductivity Resistivity Dissolved Grains per
Water Purity µS/cm M /cm Solids Gallon
at 77° F (25° C) at 77° F (25° C) (ppm of NaCl) (gpg of CaCO
2
)
Pure Water (ref. only) 0.055 18.3 0 0
Maximum Purity 0.5 2 0.206 0.010
Minimum Purity 18 0.054 8.5 0.43
Max. Potable Water
(ref. only)
1000 0.001 495 25
Grounding Requirements
Proper grounding is essential for personal safety and to prevent emission of high-frequency interference.
See Appendix A for system grounding requirements.
Connect the worktable to a high-quality earth ground, not more than 20 feet (6 m) from the table. A suitable ground
consists of a solid copper rod of at least 3/4" (19 mm) diameter driven to a depth of at least 15 feet
(4.5 m) into the earth, below the permanent moisture level. Ensure that all grounding connections are tight to avoid
excessive heating. See also Grounding in the Safety section. For additional information, consult
national or local electric codes.
Caution: All accessory modules in the HT4400 system must be grounded to earth. Use a minimum of
8 AWG (10 mm2) wire connected from the stud on the side of each module enclosure to the
worktable ground.
Note: The customer must supply all grounding wire.
Fume Emissions
Contact Hypertherm to receive the publication, Fume Emissions Testing for Plasma Arc Cutting.