SPX Cooling Technologies Marley MC 7014H081 - 7014K121 - Manual (Page 15)

Marley / MC Fluid Cooler / Engineering Data: Water Quality
15
The MC Fluid Cooler can be a very effective air
washer. Atmospheric dust able to pass through the
relatively small louver openings will enter the recirculating
water system. Increased concentrations can intensify
systems maintenance by clogging screens and
strainers—and smaller particulates can coat system heat
transfer surfaces. In areas of low flow velocity—such as
the collection basin—sedimentary deposits can provide a
breeding ground for bacteria.
In areas prone to dust and sedimentation, you should
consider installing some means for keeping the collection
basin clean. Typical devices include side stream filters
and a variety of filtration media.
Blowdown
Blowdown or Bleedoff is the continuous removal of
a small portion of the water from the open recirculating
system. Blowdown is used to prevent the dissolved
solids from concentrating to the point where they will
form scale. The amount of blowdown required depends
on the cooling range—the difference between the hot and
cold water temperatures of the closed circuit— and the
composition of the makeup water. The MC Fluid Cooler
is equipped with a blowdown line with metering valve
connected directly to the overflow. Specific blowdown
adjustment instructions and additional blowdown
information can be found in the MC Fluid Cooler
User Manual .
CAUTION
The fluid cooler must be located at such distance
and direction to avoid the possibility of contaminated
discharge air being drawn into building fresh air intake
ducts. The purchaser should certify that the location
of the fluid cooler is in compliance with applicable air
pollution, fire and clean air codes.
Water Treatment
To control the buildup of dissolved solids resulting
from water evaporation, as well as airborne impurities and
biological contaminants including Legionella, an effective
consistent water treatment program is required. Simple
blowdown may be adequate to control corrosion and
scale, but biological contamination can only be controlled
with biocides.
An acceptable water treatment program must be
compatible with the variety of materials incorporated in
a fluid cooler—ideally the pH of the recirculating water
should fall between 6.5 and 9.0. Batch feeding of the
chemicals directly into the fluid cooler is not a good
practice since localized damage to the fluid cooler is
possible. Specific startup instructions and additional water
quality recommendations can be found in the
MC Fluid Cooler User Manual which accompanies the
fluid cooler and also is available from your local Marley
sales representative.