Thermal Care NQ Series, Руководство по установке и эксплуатации

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Step 1 - Connect Main Power
Connect main power properly ensuring it matches
the voltage shown on the nameplate of the unit.
Check the electrical phase sequence prior to start-
up. Operation of the compressor with incorrect
electrical phase sequencing will result in mechanical
damage to the compressors. Check the phasing with
a phase sequence meter prior to applying power.
The proper sequence should read “ABC” on the
meter. If the meter reads “CBA”, open the main
power disconnect and switch two line leads on the
line power terminal blocks (or the unit mounted
disconnect). All components requiring electric power
are in-phase at the factory. Do not interchange any
load leads that are from the unit contactors or the
motor terminals. After making proper power
connection and grounding, turn the main power on.
Step 2 - Fill Coolant Circuit
Check to make sure all process chilled-water piping
connections are secure. Open the chiller cabinet and
fill the coolant reservoir with the proper water or
water/glycol solution following the guidelines shown
below. When using a glycol solution only use glycol
with a corrosion inhibitor. See Table 21 for
recommended glycol solutions.
System Fill Water Chemistry Requirements
Water is a unique molecule whose properties make it
ideal for heat transfer applications. It is safe: non-
flammable and non-poisonous. It is easy to handle,
widely available and inexpensive in most
industrialized areas. It is capable of absorbing more
heat per unit mass than almost any other material.
Water also has properties that need to be within
limits to avoid unwanted side effects. Water is a
“universal solvent” because it can dissolve many
solid substances to some extent and absorb gasses.
As a result, water can cause the corrosion of metals
used in a cooling system. Often water is in an open
system (exposed to air) that concentrates the ions as
water evaporates as in a cooling tower. As the
concentration exceeds the solubility of some
minerals, scale forms. The life giving properties of
water can also encourage biological growth that can
foul heat transfer surfaces.
Sometimes the source of the water can be the cause
of some of the problems. Anyone living in an area
with extremely hard water that has caused scale
build up can attest to that. Source waters available
for make-up use have an almost unlimited chemistry
variation.
To avoid the unwanted side effects associated with
water cooling, proper chemical treatment and
preventive maintenance is required for continuous
plant productivity.
Unwanted Side Effects of Improper Water Quality
•
Corrosion
•
Scale
•
Fouling
•
Biological Contamination
Cooling Water Chemistry Properties
•
Electrical Conductivity
•
pH
•
Alkalinity
•
Total Hardness
•
Dissolved gases
Some of the water chemistry properties can combine
to cause the unwanted side effects. Some of the
levels are temperature dependent (i.e. dissolved
gases).
Our chiller construction minimizes the potential for
corrosion by using stainless steel brazed plate heat
exchangers. The stainless steel resists corrosion but
is not immune to it. These, as all heat exchangers,
are susceptible to fouling that may coat the heat
transfer surfaces. Coating of these surfaces reduces
the heat transfer surface, increases the fluid
velocities and pressure drops through the heat
exchanger. All of these effects reduce the heat
transfer and affect the productivity of the plant. This
is just as true with shell and tube heat exchangers.
Chilled cooling water systems, at their simplest, have
two main heat exchangers: one that absorbs the heat
from the process and the evaporator of the chiller
that removes the heat from the system. The chiller is
only part of the entire cooling system. The system
requires proper design following sound engineering
practice and satisfying local and industry standards.
Improperly designed or installed systems may cause
unsatisfactory operation and/or system failure.
The complex nature of water chemistry requires a
specialist to evaluate and implement appropriate