22
2-15
(6) Ensure that the area is in the open or that it is adequately ventilated before breaking into the system or conducting any hot
work. A degree of ventilation shall continue during the period that the work is carried out. The ventilation should safely disperse
any released refrigerant and preferably expel it externally into the atmosphere.
(7) Where electrical components are being changed, they shall be fit for the purpose and to the correct specification. At all times
the manufacturer’s maintenance and service guidelines shall be followed. If in doubt, consult the manufacturer’s technical
department for assistance.
• The charge size is in accordance with the room size within which the refrigerant containing parts are installed.
• The ventilation machinery and outlets are operating adequately and are not obstructed.
• Marking to the equipment continues to be visible and legible. Markings and signs that are illegible shall be corrected.
• Refrigeration pipe or components are installed in a position where they are unlikely to be exposed to any substance which
may corrode refrigerant containing components, unless the components are constructed of materials which are inherently
resistant to being corroded or are suitably protected against being so corroded.
(8) Repair and maintenance to electrical components shall include initial safety checks and component inspection procedures. If a
fault exists that could compromise safety, then no electrical supply shall be connected to the circuit until it is satisfactorily dealt
with. If the fault cannot be corrected immediately but it is necessary to continue operation, an adequate temporary solution shall
be used. This shall be reported to the owner of the equipment so all parties are advised.
Initial safety checks shall include:
• That no live electrical components and wiring are exposed while charging, recovering or purging the system.
• That there is continuity of earth bonding.
● During repairs to sealed components, all electrical supplies shall be disconnected from the equipment being worked upon prior
to any removal of sealed covers, etc.
● Particular attention shall be paid to the following to ensure that by working on electrical components, the casing is not altered
in such a way that the level of protection is affected. This shall include damage to cables, excessive number of connections,
terminals not made to original specification, damage to seals, incorrect fitting of glands, etc.
● Ensure that apparatus is mounted securely.
● Ensure that seals or sealing materials have not degraded such that they no longer serve the purpose of preventing the ingress
of flammable atmospheres.
● Replacement parts shall be in accordance with the manufacturer’s specifications.
NOTE:
The use of silicon sealant may inhibit the effectiveness of some types of leak detection equipment. Intrinsically safe components
do not have to be isolated prior to working on them.
● Do not apply any permanent inductive or capacitance loads to the circuit without ensuring that this will not exceed the
permissible voltage and current permitted for the equipment in use.
● Intrinsically safe components are the only types that can be worked on while live in the presence of a flammable atmosphere.
● The test apparatus shall be at the correct rating.
● Replace components only with parts specified by the manufacturer. Unspecified parts by manufacturer may result ignition of
refrigerant in the atmosphere from a leak.
REMOVAL AND EVACUATION
CAUTION
● When breaking into the refrigerant circuit to make repairs – or for any other purpose – conventional procedures shall be used.
However, it is important that best practice is followed since flammability is a consideration.
The following procedure shall be adhered to:
• Remove refrigerant.
• Purge the circuit with inert gas.
• Evacuate.
• Purge again with inert gas.
• Open the circuit by cutting or brazing.
● The refrigerant charge shall be recovered into the correct recovery cylinders.
● The system shall be “flushed” with Oxygen free nitrogen (OFN) to render the unit safe.
● This process may need to be repeated several times.
● Compressed air or oxygen shall not be used for this task.
● Flushing shall be achieved by breaking the vacuum in the system with Oxygen free nitrogen (OFN) and continuing to fill until the
working pressure is achieved, then venting to atmosphere, and finally pulling down to a vacuum.
● This process shall be repeated until no refrigerant is within the system.
● When the final Oxygen free nitrogen (OFN) charge is used, the system shall be vented down to atmospheric pressure to enable
work to take place.
● This operation is absolutely vital if brazing operations on the pipe work are to take place.
● Ensure that the outlet for the vacuum pump is not close to any ignition sources and there is ventilation available.
01_301769_2WAY_eng.indb 41 2018/3/20 9:15:16
CHARGING PROCEDURES
CAUTION
● In addition to conventional charging procedures (see the section “Charging Additional Refrigerant” on page 1-11-15), the
following requirements shall be followed.
• Ensure that contamination of different refrigerants does not occur when using charging equipment.
• Hoses or lines shall be as short as possible to minimize the amount of refrigerant contained in them.
• Cylinders shall be kept upright.
• Ensure that the refrigeration system is earthed prior to charging the system with refrigerant.
• Label the system when charging is complete (if not already).
• Extreme care shall be taken not to overfill the refrigeration system.
● Prior to recharging the system, it shall be pressure-tested with the appropriate purging gas.
● The system shall be leak-tested on completion of charging but prior to commissioning.
● A follow up leak test shall be carried out prior to leaving the site.
● Electrostatic charge may accumulate and create a hazardous condition when charging or discharging the refrigerant.
To avoid fire or explosion, dissipate static electricity during transfer by grounding and bonding containers and equipment before
charging / discharging.
DECOMMISSIONING
CAUTION
● Before carrying out this procedure, it is essential that the technician is completely familiar with the equipment and all its details.
● It is recommended good practice that all refrigerants are recovered safely.
● Prior to the task being carried out, an oil and refrigerant sample shall be taken in case analysis is required prior to re-use of
reclaimed refrigerant.
● It is essential that electrical power is available before the task is commenced.
a) Become familiar with the equipment and its operation.
b) Isolate system electrically.
c) Before attempting the procedure ensure that:
• Mechanical handling equipment is available, if required, for handling refrigerant cylinders.
• All personal protective equipment is available and being used correctly.
• The recovery process is supervised at all times by a competent person.
• Recovery equipment and cylinders conform to the appropriate standards.
d) Pump down refrigerant system, if possible.
e) If a vacuum is not possible, make a manifold so that refrigerant can be removed from various parts of the system.
f) Make sure that cylinder is situated on the scales before recovery takes place.
g) Start the recovery machine and operate in accordance with manufacturer’s instructions.
h) Do not overfill cylinders. (No more than 80 % volume liquid charge).
i) Do not exceed the maximum working pressure of the cylinder, even temporarily.
j) When the cylinders have been filled correctly and the process completed, make sure that the cylinders and the equipment
are removed from site promptly and all isolation valves on the equipment are closed off.
k) Recovered refrigerant shall not be charged into another refrigeration system unless it has been cleaned and checked.
● Electrostatic charge may accumulate and create a hazardous condition when charging or discharging the refrigerant.
To avoid fire or explosion, dissipate static electricity during transfer by grounding and bonding containers and equipment before
charging / discharging.
● Equipment shall be labelled stating that it has been de-commissioned and emptied of refrigerant.
● The label shall be dated and signed.
● Ensure that there are labels on the equipment stating the equipment contains flammable refrigerant.
01_301769_2WAY_eng.indb 42 2018/3/20 9:15:16
SM830266-00_大洋州向けR32シングルTD&SM.indb 15 18/03/29 11:58:32
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