67
EN
INFORMATION SERVICING
9. Checks to electrical devices
Repair and maintenance to electrical components shall include initial safety checks and component inspection procedures. If a fault ex-
ists 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 that all parties are advised of the situation.
Initial safety checks shall include:
•
that capacitors are discharged: this shall be done in a safe manner to avoid the possibility of sparking
•
that there no live electrical components and wiring are exposed while charging, recovering or purging the system;
•
that there is continuous earth bonding.
10. Repairs to sealed components
10.1 During repairs to sealed components, all electrical supply shall be disconnected from the equipment being worked on prior to the
removal of any sealed covers and similar. If it is absolutely necessary to maintain 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.
10.2 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 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.
11. 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 air from a leak.
12. Cabling
Check that cabling will not be subject to wear, corrosion, excessive pressure, vibration, sharp edges or any other adverse environmen-
tal effects. The check shall also take into account the effects of aging or continual vibration from sources such as compressors or fans.
13. 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.
14. 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 equip-
ment 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. 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 or 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 shutting 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.
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.
NOTE:
