JOHNSON CONTROLS
27
FORM 155.17-N1
ISSUE DATE: 4/1/2013
7
Absorber / Condenser and Evaporator water must be
free of corrosive species or inhibited to prevent at-
tack of the waterside tubing. Impurities and dissolved
solids can cause scaling that reduces heat exchanger
efficiency and causes corrosion of tubes. Corrosion,
in turn, can result in more serious problems, such as
metal wastage and contamination of the solution and
refrigerant if through-wall pitting occurs.
YORK ParaFlow
TM
Absorption can only deliver de-
sign output and efficiency if they are properly operated
and maintained. One of the most important elements
of proper maintenance is the cleanliness of the tubes
to prevent fouling, scaling and corrosion during daily
operations and shutdowns.
It is the responsibility of the owner (operator) of this
equipment to engage the services of an experienced
and reputable water treatment specialist for both the
initial charging of the system and its continuous moni-
toring and treatment. Improperly treated or maintained
water will result in decreased efficiency, high operat-
ing costs and premature failure due to waterside cor-
rosion.
For water treatment programs to be acceptable, they
must protect all exposed metal (i.e., carbon steel, cop-
per and brass) from corrosive attack. The use of cor-
rosion inhibitors must be effective at low concentra-
tions, must not cause deposits on the metal surfaces,
and must remain effective under a broad range of pH,
temperature, water quality and heat flux. Furthermore,
the inhibitor package must prevent scale formation
and disperse deposits while having a minimal environ-
mental impact when discharged.
Water samples should be collected and analyzed on
at least a monthly basis by the water treatment spe-
cialist. A quarterly review with the treatment supplier
should address the conditions of the water systems and
develop action plans based on these analyses. A third
party water consulting company can help oversee the
water treatment programs in order to properly protect
the physical plant and avoid costly downtime.
It is equally important that the owner (operator) of
the equipment performs tube cleaning and inspection
of the absorber, condenser and evaporator waterside
tubes at the frequencies recommended in the Tube
Maintenance Section of the “Preventative Mainte-
nance Schedule” located in manual 155.17-OM1. In
addition to periodic cleaning with tube brushes, tubes
must be inspected for wear and corrosion. Tube fail-
ures usually occur due to corrosion, erosion, and fa-
tigue due to thermal stress. Eddy current analysis and
visual inspection by boroscope of all tubes are invalu-
able preventative maintenance methods. These pro-
vide a quick method of determining waterside tube
condition at a reasonable cost.
Your local Johnson Controls Service Representative
will be more than happy to supply any or all of these
services.
SECTION 7 – TOWER WATER TREATMENT
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