Hypertherm HPR260 Manual Gas Preventive Maintenance Program Rev.5 - Manual (Page 89)

INSTALLATION
3-40 HPR260 Auto Gas Instruction Manual
5
Water purity requirements
It is critical to maintain a low level of calcium carbonate in the coolant to avoid reduced performance of the torch or
cooling system.
Always use water that meets the minimum and maximum specifications in the table below when using a custom coolant
mix.
Water that does not meet the minimum purity specifications below can cause excessive deposits on the nozzle that will
alter the water flow and produce an unstable arc.
Water that does not meet the maximum purity specifications below can also cause problems. Deionized water that is too
pure will cause leaching problems with the coolant system plumbing.
Use water purified by any method (deionization, reverse osmosis, sand filters, water softeners, etc.) as long as the water
purity meets the specifications in the table below. Contact a water specialist for advice in choosing a water filtration
system.
Coolant for hot operating temperatures (above 38° C / 100° F)
Use a custom coolant mix when operating in temperatures above 38° C (100° F).
Treated water (with no propylene glycol) can only be used as coolant when operating temperatures are never below
0° C (32° F). For operations in very warm temperatures treated water will provide the best cooling properties.
Treated water refers to a mixture of purified water, that meets the specifications below, and 1 part benzotriazole (BZT) to
300 parts of water. BZT (128020) acts as a corrosion inhibitor for the copper based coolant system contained in the
plasma system.
Water purity measurement method
Water purity
Conductivity
S/cm
at 25° C
Resistivity
mΩ-cm
at 25° C
Dissolved solids
(ppm of NaCl)
Grains per gallon
(gpg of CaCO
2
)
Pure water (for reference 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
Maximum potable water
(for reference only)
1000 0.001 495 25