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Appendix B
Piping System Flushing
Procedure
Prior to connecting the chiller to the condenser and chilled
water loop, the piping loops shall be flushed with a
detergent and hot water (110-130°F) mixture to remove
previously accumulated dirt and other organics. In old
piping systems with heavy encrustation of inorganic
materials consult a water treatment specialist for proper
passivation and/or removal of these contaminants.
During the flushing, 30 mesh (max.) Y-strainers (or
acceptable equivalent) shall be in place in the system
piping and examined periodically as necessary to remove
collected residue. The use of on-board chiller strainers
shall not be acceptable. The flushing process shall take no
less than 6 hours or until the strainers when examined
after each flushing are clean. Old systems with heavy
encrustation shall be flushed for a minimum of 24 hours
and may take as long as 48 hours before the filters run
clean. Detergent and acid concentrations shall be used in
strict accordance with the respective chemical
manufacturer's instructions. After flushing with the
detergent and/or dilute acid concentrations the system
loop shall be purged with clean water for at least one (1)
hour to ensure that all residual cleaning chemicals have
been flushed out.
Prior to supplying water to the chiller the Water Treatment
Specification shall be consulted for requirements
regarding the water quality during chiller operation. The
appropriate chiller manufacturer's service literature shall
be available to the operator and/or service contractor and
consulted for guidelines concerning preventative
maintenance and off-season shutdown procedures.
CG-SVX044B-EN
Water Treatment Requirements
Supply water for both the chilled water and condenser
water circuits shall be analyzed and treated by a
professional water treatment specialist who is familiar
with the operating conditions and materials of
construction specified for the chiller's heat exchangers,
headers and associated piping. Cycles of concentration
shall be controlled such that recirculated water quality for
compact chillers using 316 stainless steel brazed plate heat
exchangers and carbon steel headers is maintained within
the following parameters.
Table 6.
Water property limits
Water Property
3 -
Alkalinity (HCO
)
2-
Sulfate (SO
)
4
-
2-
HCO
/ SO
3
4
Electrical Conductivity
pH
Ammonia (NH
)
3
-
Chlorides (Cl
)
Free Chlorine (Cl
)
2
Hydrogen Sulfide (H
S)
2
Free (aggressive) Carbon Diox-
ide(CO
)
2
Total Hardness (°dH)
Nitrate (NO
)
3
Iron (Fe)
Aluminum (Al)
Manganese (Mn)
Concentration Limits
70-300 ppm
Less than 70 ppm
Greater than 1.0
10 - 500 μS/cm
7.5 – 9.0
Less than 2 ppm
Less than 300 ppm
Less than 1 ppm
Less than 0.05 ppm
Less than 5 ppm
4.0 - 8.5
Less than 100 ppm
Less than 0.2 ppm
Less than 0.2 ppm
Less than 0.1 ppm
53
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