CyberOne EC DX IOM Manual
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.
2.8.1.1
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.
2.8.2
DX Unit Charging Requirements
When performing the specific DX charging procedures in this
section, follow these best practices:
Ensure that contamination of different refrig-
erants does not occur when using charging
equipment. Hoses or lines must be as short as
possible to minimize the amount of refrigerant
contained in them.
Keep cylinders upright.
Ensure the refrigeration system is grounded
to Earth before charging the system with re-
frigerant.
Label the system when charging is complete (if
it is not labeled already).
Exercise extreme care to avoid overfilling the
refrigeration system.
Before recharging the system, it must be pressure tested with
oxygen-free nitrogen (OFN). The system must be leak tested
upon completion of charging but prior to commissioning. A
follow-up leak test must be carried out prior to leaving the site.
2.8.3
Remote Air-Cooled Systems (AR/AHU)
Remote air-cooled units are provided with a dry nitrogen
holding charge, which must be removed before piping and
charging the unit.
NOTE
Refrigerant charging must be performed by a
qualified air conditioning technician.
CyberOne EC systems use R407Crefrigerant. Refrigerant
charging pressures vary depending on the type of
refrigerant used in the unit. Before charging, check the unit
nameplate to confirm the type of refrigerant to use. Tables
are provided in Section 2.8.8 showing the
temperature/pressure characteristics for R407C.
CAUTION
POE oil is used in systems with R407C
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 the entire system sealed as
much as possible and minimize exposure of the
POE oil to outside air.
2.8.4
R407C Refrigerant
R407C is a refrigerants recognized for being safer for the
environment. It contains no chlorine, the component in
HCFC’s that destroy the earth’s ozone layer. However, the
same care should be taken to prevent leakage because
R407C can contribute to the greenhouse effect if released.
If the refrigerant gas is released in an enclosed space, it can
become a suffocant.
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. Typically, the
composition of R407C vapor is different than that of R407C
liquid within a contained system. The composition of liquid
R407C refrigerant remains relatively constant, however, the
refrigerant vapor tends to separate into its component parts
even when circulating.
Refrigerant R407C is a blended refrigerant that consists
of component parts; however, the component parts of the
refrigerant have the same composition at various operating
temperature/pressures in the liquid phase and gas phase
reducing the temperature glide effect experienced with
R407C.
2.8.5
Estimating Refrigerant Charge
When charging a system with R407C refrigerant it will be
necessary to weigh in the refrigerant and confirm by
checking the superheat and sub-cooling temperatures.
You can estimate the amount of refrigerant needed by
adding the amount of refrigerant required for the condenser
(see the condenser manual provided separately) plus the
refrigerant piping (Table 1) plus the refrigerant for the A/C
unit (Table 2). The values in Table 2 are the estimated weights
for the compressor circuit. Depending upon site specific
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