AEG AXP26V578HW User Manual download pdf (Page 20)

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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.

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 ammable atmosphere.

The test apparatus shall be at the correct

rating. Replace components only with

parts specied by the manufacturer.

Other parts may result in the ignition of

refrigerant in the atmosphere from a leak.

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.

Cabling

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 ame) shall not be used.

Detection of ammable refrigerants

When breaking into the refrigerant

circuit to make repairs – or for any other

purpose – conventional procedures

shall be used. However, it is important

that best practice is followed since

ammability is a consideration. The

following procedure shall be adhered to:

•

Remove refrigerant;

•

Purge the circuit with inert gas;

•

Evacuate;

•

Purge again with inert gas;

•

Open the circuit by cutting or brazing.

The following leak detection methods

are deemed acceptable for systems

containing ammable refrigerants.

Electronic leak detectors shall be used

to detect ammable 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 conrmed.

Leak detection uids 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 ames

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 o 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.

Removal and evacuation

Leak detection methods

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 aected. This shall

include damage to cables, excessive

number of connections, terminals not

made to original specication, damage

to seals, incorrect tting 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 ammable

atmospheres. Replacement parts

shall be in accordance with the

manufacturer’s specications.

The refrigerant charge shall be recovered

into the correct recovery cylinders. The

system shall be “ushed” with OFN to

render the unit safe. This process may

need to be repeated several times.

Compressed air or oxygen shall not

be used for this task. Flushing shall be

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AEG AXP26V578HW User Manual Page 20

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