SECTION 4 3000P-4500 USER MANUAL
53
Table 4-2: VENTILATION REQUIREMENTS
WATER SYSTEM VENTING
Vent the system upon installation or after draining the
system on start-up:
1. Open the water valve(s) allowing water to
flow to the system.
2. Open the vent cocks (located on top of the
aftercooler and the lubricant cooler) and
allow all air to escape from the system.
When water is observed at the vent cocks,
close them.
The system is now vented.
DRAINING THE WATER SYSTEM
If the system needs to drained completely, follow the
steps outlined below:
1. At the rear of the unit. Disconnect both the
inlets and discharge water lines.
2. Remove the drain plugs located at the bot-
tom of the aftercooler and lubricant cooler.
3. Allow the system to drain completely.
WATER QUALITY RECOMMENDATIONS
Water quality considerations are crucial to the
effective operation of a water-cooled compressor and
yet are the most often ignored. Premature failure of
components can often be traced to a reduction in
heat-transfer rate that has resulted from a reduced
flow rate due to scale build-up in water-cooling lines
or the coolers themselves.
SCALE
Scale is formed from calcium carbonate, which
precipitates out of water. Calcium content tends to be
higher in water taken from wells than water taken
from the surface of lakes. A higher pH value will also
assist in the formation of lime scale. In all cases
calcium will form scale when water that has dissolved
calcium is heated. It then forms lime-scale on
surfaces such as the inside of pipes and the tubing
that comprises water coolers. Scale formation on the
inside of pipes and inside of heat exchangers acts as
a thermal insulator. This causes coolers to be less
effective, and piping to have reduced water flow,
making them less effective. Over time lime scale
build-up can reduce water flow by 80% or greater.
This renders the cooling system ineffective and will
damage the system. Scale can be controlled with
water treatment.
CORROSION
As contrasted to lime scale build-up, corrosion
eventually causes a reduction in the wall thickness of
pipes. High levels of dissolved oxygen and low pH
levels assist in the creation of corrosive scale. A thin
coating of lime scale is often beneficial in helping to
prevent corrosion from forming.
BIOLOGICAL AND ORGANIC FOULING (SLIME)
The heightened temperatures of compressor cooling
operations help to reduce the likelihood that organic
fouling will become a major concern. In the event of
an infestation, commercial chemical shock
treatments are available to control any outbreaks.
To ensure maximum life expectancy and best
performance of the compressor cooling system, refer
to Table 4-3: WATER TESTS on page 54.
Cooling Type Air-Cooled with Aftercooler Water-Cooled
Motor HP/kW 40/30 50/37 60/45 40/30 50/37 60/45
Fan Air cfm/m3/hr 5,000/8,500 5,000/8,500 6,000/10,200 700/1,200 700/1,200 700/1,200
Ventilating Air/Heat
Rejection
BTU/Hour
114,500 142,000 171,000 10,600 13,300 15,800
KCal/Hour 28,800 35,700 46,216 2,670 3,350 4,000
Cooling Water/
Heat Rejection
BTU/Hour
114,500 142,000 171,100
KCal/Hour 28,800 35,700 43,040
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