CyberAiR DX Floor Mounted IOM Manual
2.9 System Charging Procedures
2.9.1
Water-Water/Glycol Systems
All self-contained water-water/glycol cooled units
(units that require no refrigerant field piping) are
factory charged with R-410A refrigerant. No field
charging is required. The following precautions must
be observed when installing and filling the
water/glycol loop:
•
The
piping
system must be
cleaned
prior
to adding water/glycol to the system.
•
Glycol must be
mixed
with water
before
it is
added to the system. All
air
must be
bled
from the
piping system. Use only
water/glycol solution
with
inhibitors
for corrosion protection.
CAUTION
The piping system must be flushed prior to
operating the system. Failure to do so will
result in equipment problems.
1. Open the vent valve at highest point of
the system.
2. Fill the system until the solution is discharging
from the vent with minimal signs of foaming due
to air in the system.
2.9.1.1 Pump
If a pump is to be used, ensure the system is filled
before turning the pump on. The pump is not self-
priming so it is important that there is a pressure on
the suction inlet.
CAUTION
Do not run the pump dry.
If the pump has no pressure on the discharge side,
leave the discharge valve partially shut to create a
back pressure in the pump so that liquid can build
up in the impeller housing to keep the impeller
housing from getting too hot. Make sure there is
always liquid flowing through the pump to cool the
impeller and
housing. If there is no liquid leaving the pump, shut
the pump off immediately to prevent damage to the
pump. Check for proper rotation of the motor
observing the arrow on the side of the impeller.
2.9.2
Refrigerant Charging
2.9.2.1 Remote Air-Cooled Systems
Remote air-cooled systems are provided with a dry
nitrogen holding charge which must be removed
before piping and charging the unit. Before
charging, check the unit nameplate to confirm that
charging
is performed with the correct type of
refrigerant. CyberAiR systems utilize R-410A
refrigerant.
NOTE
Refrigerant charging must be performed by
a qualified air conditioning technician.
R-410A is a blended refrigerant recognized for
being safer for the environment. Refrigerants that
are multi-component blends have component
parts with different volatilities that result in a
change in
composition and saturation temperature as
evaporation and condensation occur. The
composition of liquid
R-410A refrigerant, however, remains
relatively constant.
CAUTION
POE oil is used in systems with R-410A
refrigerant. POE oil quickly absorbs moisture
when exposed to air. High POE oil moisture
levels react with refrigerant to form acid,
which results in system contamination. Keep
entire system sealed as much as possible
and minimize exposure of POE oil to outside
air.
R-410A operates at high pressures which must be
considered when checking the operating
temperatures/ pressures while charging or
troubleshooting the system. Tables are provided in
Section 2.9.6 showing the temperature/pressure
characteristics for R-410A.
2.9.3
Estimating Refrigerant Charge
When charging a system with R-410A refrigerant it
will be necessary to weigh in the refrigerant and
confirm the charge is correct by checking the
superheat and subcooling temperatures (see Section
2.9.6.1)
.
You can estimate the amount of refrigerant
needed by adding the amount of refrigerant
required for the
A/C unit (Table 1) plus the condenser (Table 2) plus
the interconnecting refrigerant piping between the
A/C unit and the condenser (Table 3).
The values in the tables are the estimated weights
for the refrigerant circuits. Depending upon site
specific conditions, refrigerant may need to be
added or removed when fine tuning the charge to
obtain the correct superheat and sub-cooling
temperatures.
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