Fujitsu AJ 040KCTAH Series Installation Manual page 4

2-7 Checks to the refrigerating equipment
• 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 following checks shall be applied to installations using flammable refrigerants:
- the actual refrigerant charge 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;
- if an indirect refrigerating circuit is being used, the secondary circuit shall be checked
for the presence of refrigerant;
- marking to the equipment continues to be visible and legible. Markings and signs that
are illegible shall be corrected;
- refrigerating 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.
2-8 Checks to electrical devices
• 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 capacitors are discharged: this shall be done in a safe manner to avoid possibil-
ity of sparking;
- that no live electrical components and wiring are exposed while charging, recovering
or purging the system;
- that there is continuity of earth bonding.
3. Repairs to sealed components
• 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.
• If it is absolutely necessary to have an electrical supply to equipment during servicing,
then a permanently operating form of leak detection shall be located at the most
critical point to warn of a potentially hazardous situation.
• 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 af-
fected. This shall include damage to cables, excessive number of connections, termi-
nals not made to original specification, damage to seals, incorrect fitting of glands, etc.
• Ensure that the apparatus is mounted securely.
• Ensure that seals or sealing materials have not degraded to the point that they no lon-
ger serve the purpose of preventing the ingress of flammable atmospheres. Replace-
ment parts shall be in accordance with the manufacturer's specifications.
4. Repair to intrinsically safe components
• 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. Other parts may
result in the ignition of refrigerant in the atmosphere from a leak.
NOTES:
• The use of silicon sealant can inhibit the effectiveness of some types of leak detection
equipment.
• Intrinsically safe components do not have to be isolated prior to working on them.
5. Cabling
• Check that cabling will not be subject to wear, corrosion, excessive pressure, vibration,
sharp edges or any other adverse environmental effects.
• The check shall also take into account the effects of aging or continual vibration from
sources such as compressors or fans.
6. Detection of flammable refrigerants
• Under no circumstances shall potential sources of ignition be used in the searching for
or detection of refrigerant leaks.
• A halide torch (or any other detector using a naked flame) shall not be used.
7. Leak detection methods
• The following leak detection methods are deemed acceptable for all refrigerant
systems.
• Electronic leak detectors may be used to detect refrigerant leaks but, in the case of
flammable refrigerants, the sensitivity may not be adequate, or may need recalibration.
(Detection equipment shall be calibrated in a refrigerant-free area.)
• Ensure that the detector is not a potential source of ignition and is suitable for the
refrigerant used.
• 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.
• Leak detection fluids are also suitable for use with most refrigerants but the use of
detergents containing chlorine shall be avoided as the chlorine may react with the
refrigerant and corrode the copper pipe-work.
NOTE:
Examples of leak detection fluids are
- bubble method,
- fluorescent method agents.
• If a leak is suspected, all naked flames shall be removed / extinguished.
• If a leakage of refrigerant is found which requires brazing, all of the refrigerant shall be
recovered from the system, or isolated (by means of shut off valves) in a part of the
system remote from the leak.
En-3
CAUTION
8. Removal and evacuation
• When breaking into the refrigerant circuit to make repairs – or for any other purpose
– conventional procedures shall be used. However, for flammable refrigerants it is
important that best practice is followed since flammability is a consideration. The fol-
lowing procedure shall be adhered to:
- remove refrigerant;
- purge the circuit with inert gas (optional for R32);
- evacuate (optional for R32);
- purge with inert gas (optional for R32);
- open the circuit by cutting or brazing.
• The refrigerant charge shall be recovered into the correct recovery cylinders.
• This process may need to be repeated several times.
• Compressed air or oxygen shall not be used for purging refrigerant systems.
• This process shall be repeated until no refrigerant is within the system.
• When the final oxygen-free nitrogen 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 potential ignition
sources and that ventilation is available.
9. Charging procedures
• In addition to conventional charging procedures, the following requirements shall be
followed.
- Ensure that contamination of different refrigerants does not occur when using charg-
ing equipment.
- Hoses or lines shall be as short as possible to minimize the amount of refrigerant
contained in them.
- Cylinders shall be kept in an appropriate position according to the instructions.
- Ensure that the refrigerating system is earthed prior to charging the system with
refrigerant.
- Extreme care shall be taken not to overfill the refrigerating 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.
10. Decommissioning
• Before carrying out this procedure, it is essential that the technician is completely
familiar with the equipment and all its detail.
• 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 recovered 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 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 refrigerating system unless
it has been cleaned and checked.
11. Labelling
• Equipment shall be labelled stating that it has been de-commissioned and emptied of
refrigerant.
• The label shall be dated and signed.
• For appliances containing flammable refrigerants, ensure that there are labels on the
equipment stating the equipment contains flammable refrigerant.
CAUTION