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Idiomas disponibles
Idiomas disponibles
Inspection on Maintenance Environment
Before operation, the refrigerant leaked in the room is not allowed.
The area of the room in which maintenance is made shall be in line with the nameplate.
Continuous ventilation shall be maintained during maintenance.
Open fire or high-temperature heat source higher than 548 degree which can easily give birth to open fire is
not allowed inside the room within the maintenance area.
During maintenance, the phones and the radioactive electronics of all the operators inside the room must be
powered off.
One dry powder or carbon dioxide extinguisher shall be equipped inside the maintenance area, and the
extinguisher must be under available state.
Maintenance Site Requirements
The maintenance site shall be provided with favorable ventilation and must be flat. Arrangement of the
maintenance site inside the basement is not allowed.
Welding zone and non-welding zone shall be divided at the maintenance site, and shall be clearly marked. A
certain safety distance must be guaranteed between the two zones.
Ventilators shall be installed at the maintenance site, and exhaust fans, fans, ceiling fans, floor fans and
dedicated exhaust duct can be arranged, to meet the requirements of ventilation volume and uniform exhaust, and
to avoid accumulation of refrigerant gas.
Leak detection equipment for flammable refrigerant shall be equipped, with relevant management system
being established. Whether the leak detection equipment is under available state shall be confirmed before
maintenance.
Sufficient dedicated vacuum pumps of flammable refrigerant and refrigerant charging equipment shall be
equipped, with relevant management system for maintenance equipment being established. It shall be guaranteed
that the maintenance equipment can only be used for vacuumizing and charging of one type of flammable
refrigerant, and mixed usage is not allowed.
The master power switch shall be arranged outside the maintenance site, with protective (anti-explosive)
device being equipped.
Nitrogen cylinders, acetylene cylinders and oxygen cylinders shall be placed separately. The distance
between the gas cylinders above and the working area involved in open fire shall be at least 6m. The anti-backfire
valve shall be installed for the acetylene cylinders. The color of the acetylene cylinders and oxygen cylinders
installed shall meet the international requirements.
The warning sign of "No Fire" shall be arranged inside the maintenance area.
Fire control device suitable for electric appliance such as the dry powder extinguisher or carbon dioxide
extinguisher shall be equipped, and shall always be under the available state.
The ventilator and other electrical equipment at the maintenance site shall be relatively fixed, with
standardized pipe routing. Temporary wires and sockets at the maintenance site are not allowed.
Leak Detection Methods
The environment in which the refrigerant leakage is checked shall be free from potential ignition source.
Leak detection with halogen probes (or any other detector with open fire) shall be avoided.
For the system containing flammable refrigerant, leak detection may be realized with electronic leak
detection equipment. During leak detection, the environment in which the leak detection equipment is calibrated
shall be free from refrigerant. It shall be guaranteed that the leak detection equipment will not become potential
ignition source, and is applicable to the refrigerant to be detected. Leak detection equipment shall be set at a
percentage of the LFL of the refrigerant and shall be calibrated to the refrigerant employed, and the appropriate
percentage of gas (25 % maximum) is confirmed.
The fluid used for leak detection shall be applicable to most of the refrigerant. The use of chlorine-
containing solvent shall be avoided, to avoid chemical reaction between chlorine and refrigerant and corrosion to
copper pipelines.
In case leakage is suspected, the open fire at the site shall be evacuated or be put out.
In case welding is required at the leakage position, all the refrigerants shall be recovered, or be isolated at a
position far from the leak point with a stop valve. Before and during welding, the whole system shall be purified
with OFN.
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Safety Principles
During product maintenance, favorable ventilation shall be guaranteed at the maintenance site, and the close
of all the doors/windows is not allowed.
Operation with open fire is not allowed, including welding and smoking. The use of phones is also not
allowed. The user shall be informed that cooking with open fire is not allowed.
During maintenance in a dry season, when the relative humidity is less than 40%, anti-static measures shall
be taken, including the wearing of cotton clothes and cotton gloves.
In case the leakage of flammable refrigerant is identified during maintenance, forced ventilation measures
shall be taken immediately, and the source of leak shall be plugged.
In case the product damaged must be maintained by disassembling the refrigeration system, the product
must be delivered to the maintenance point. Welding of refrigerant pipelines at the user's site is not allowed.
During maintenance, in case re-treatment is required due to lack of fittings, the air conditioner shall be reset.
The refrigeration system must be safely earthed in the whole course of maintenance.
For the door-to-door service with refrigerant cylinders, the refrigerant charged inside the cylinder cannot
exceed the specified value. The cylinder placed in vehicles or at the installation/maintenance site shall be fixed
perpendicularly and be kept away from heat sources, ignition source, source of radiation and electric appliance.
Maintenance Items
Maintenance Requirements
Before the refrigeration system is operated, the circulating system shall be cleaned with nitrogen. Afterwards,
the outdoor unit shall be vacuumized, the duration of which cannot be less than 30 minutes. Finally, 1.5~2.0MPa
OFN shall be used for nitrogen flushing (30 seconds~1 minute), to confirm the position requiring treatment.
Maintenance of the refrigeration system is only allowed after the residual gas of flammable refrigerant is removed.
During the use of refrigerant charging tools, cross contamination of different refrigerants shall be avoided.
The total length (including the refrigerant pipelines) shall be shortened as much as possible, to reduce the residual
of refrigerant inside.
The cylinders of refrigerant shall be kept upright, and be fixed.
Before refrigerant charging, the refrigeration system shall be earthed.
The refrigerant charged shall be of the type and volume specified on the nameplate. Excessive charging is
not allowed.
After maintenance of the refrigeration system, the system shall be sealed with a safe manner.
The maintenance in progress shall not damage or lower the original class of safety protection of the system.
Maintenance of Electrical Components
Partial of the electrical component under maintenance shall be subject to inspection on refrigerant leakage
with dedicated leak detection equipment.
After the maintenance, the components with safety protection functions cannot be disassembled or removed.
During the maintenance of sealing elements, before opening the seal cover, the air conditioner shall be
powered off first. When power supply is required, continuous leak detection shall be carried out at the most
dangerous position, to avoid potential risks.
During maintenance of electrical components, the replacement of enclosures shall not affect the level of
protection.
After maintenance, it shall be guaranteed that the sealing functions will not be damaged or the sealing
materials will not lose the function of preventing the entry of flammable gas due to aging. The substitute
components shall meet the recommended requirements of the air conditioner manufacturer.
Maintenance of Intrinsically Safe Elements
The intrinsically safe element refers to the components working continuously inside flammable gas without any
risks.
Before any maintenance, leak detection and inspection on earthing reliability of the air conditioner must be
carried out, to ensure no leakage and reliable earthing.
In case the allowable voltage and current limit may be surpassed during the service of the air conditioner,
any inductance or capacitance cannot be added in the circuit.
Only the elements appointed by the air conditioner manufacturer can be used as the parts and components
replaced, or otherwise a fire may be triggered in case of refrigerant leakage.
For the maintenance not involved in system pipelines, the system pipelines shall be well protected, to ensure
that no leakage will be caused due to maintenance.
After maintenance and before test run, the air conditioner must be subject to leak detection and inspection on
earthing reliability with leak detection equipment or leak detecting solution. It shall be guaranteed that the startup
inspection is carried out without leakage and under reliable earthing.
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Removal and Vacuumizing
The maintenance or other operations of the refrigeration circuit shall be made as per conventional procedures.
Moreover, the flammability of refrigerant shall also be mainly considered. The following procedures shall be
followed:
Refrigerant clearing;
Pipeline purification with inert gas;
Vacuumizing;
Pipeline purification again with inert gas;
Pipeline cutting or welding. The refrigerant shall be recovered to a proper cylinder. The system shall be
purged with OFN, to ensure safety. The step above may need to be repeated for several times. Compressed air or
oxygen cannot be used for purging.
In the course of purging, OFN shall be charged inside the refrigeration system under vacuum state, to reach
the operating pressure. Afterwards, the OFN shall be discharged to the atmosphere. Finally, the system shall be
vacuumized. The step above shall be repeated until all the refrigerants in the system are cleared. The OFN charged
for the last time shall be discharged to the atmosphere. Afterwards, the system can be welded. The operation
above is necessary in case of pipeline welding.
It shall be guaranteed that no alight fire source is around the outlet of the vacuum pump and the ventilation is
favorable.
Welding
Favorable ventilation must be guaranteed in the maintenance area. After the maintenance machine is subject
to the vacuumizing above, the system refrigerant can be discharged on the outdoor unit side.
Before the outdoor unit is welded, it must be guaranteed that no refrigerant is inside the outdoor unit and the
system refrigerant has been discharged and cleared.
The refrigeration pipelines cannot be cut with a welding gun under any circumstance. The refrigeration
pipelines must be disassembled with a pipe cutter, and the disassembly must be carried out around a ventilation
opening.
Refrigerant Charging Procedures
The following requirements are added as the supplementation of conventional procedures:
During the use of refrigerant charging tools, cross contamination of different refrigerants shall be avoided.
The total length (including the refrigerant pipelines) shall be shortened as much as possible, to reduce the residual
of refrigerant inside;
The cylinders of refrigerant shall be kept upright;
Before refrigerant charging, the refrigeration system shall be earthed;
A label must be pasted on the refrigeration system after refrigerant charging;
Excessive charging is not allowed; the refrigerant shall be charged slowly;
In case system leakage is identified, refrigerant charging is not allowed unless the leak point is plugged;
During refrigerant charging, the charging amount shall be measured with an electronic scale or a spring
scale. The connecting hose between the refrigerant cylinder and the charging equipment shall be relaxed
appropriately, to avoid impact on the measuring accuracy due to stress.
Requirements on storage site of refrigerant
The cylinder of refrigerant shall be placed in a -10~50°C environment with favorable ventilation, and
warning labels shall be pasted;
The maintenance tool in contact with the refrigerant shall be stored and used separately, and the
maintenance tool of different refrigerants cannot be mixed.
Scrapping and Recovery
Scrapping
Before scrapping, the technician shall be completely familiar with the equipment and all its features. The safe
recovery of refrigerant is recommended. In case the refrigerant recovered needs to be reused, before which the
sample of refrigerant and oil shall be analyzed. The power supply required shall be guaranteed before tests.
(1)
The equipment and operation shall be well known;
(2)
Power supply shall be switched off;
(3)
The followings shall be guaranteed before scrapping:
The mechanical equipment shall be convenient for operation on the cylinder of refrigerant (if necessary);
All personal protective equipment is available and being used correctly;
The whole course of recovery shall be guided by qualified personnel;
The recovery equipment and cylinders shall be in line with corresponding standards.
(4)
The refrigeration system shall be vacuumized if possible;
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