Keystone KSTAP10PINV User Manual page 11

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,
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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.
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 effects. The check shall also take into account the effects 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. Leak detection fluids are 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. 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.
Oxygen free nitrogen (OFN) shall then be purged through the system both before and during the
brazing process.
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