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, and 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.

10) Repairs to sealed components

a) 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.

b) 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. Re-

placement 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. Instrinsically safe

components do not have to be isolated prior to working on them.

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. Intrinscially 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.

12) 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.

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.

The following leak detection methods are deemed acceptable for systems containing flammable refrigerants system.

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. 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 refrig erants 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 flu ids are

•

bubble method

•

fluore scent method agents

If a leak is suspected, ali naked flames shall be removed/extinguished.

If a leakage of refrigerant is found which requires brazing, ali 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.

Removal of refrigerant shall be accord ing to Clause DD.9.

14) Removal and evacuation

When breaking into the refrigerant circuit to make repairs of 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 with inert gas;

•

Open the circuit by cutting or brazing.

Cod. 3541V991 - Rev. 00 - 09/2021