Midea MPPD40C User Manual page 9

9)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
possibility of sparking; That there no live electrical components and wiring are
exposed while charging, recovering or purging the system; That there is continuity
of earth bonding.
7.Repairs to sealed components
1)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.
2)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 a ected. 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 e ectiveness of some types of leak
detection equipment. Intrinsically safe components do not have to be isolated prior
to working on them.
8.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.
9.Cabling
Check that cabling will not be subject to wear, corrosion, excessive pressure,
vibration, sharp edges or any other adverse environmental e ects. The check shall
also take into account the e ects of aging or continual vibration from sources such
as compressors or fans.
10.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.
11.Leak detection methods
The following leak detection methods are deemed acceptable for systems
containing flammable refrigerants. Electronic leak detectors shall be used to detect
flammable refrigerants, but the sensitivity may not be adequate, or may need
re-calibration. (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.
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