Manual Sencor SDH 2020 (page 12 of 13) (English)

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- 12 - 09/2020

SERVICING INSTRUCTIONS

1.1 Area check

Before starting work on asystem containing flammable refrigerants, safety checks are

necessary to ensure that the risk of ignition is minimized. When repairing acooling

system, the following measures must be adhered to prior to performing any work.

1.2. Work procedure

Work must be performed following a controlled procedure so that the risk of

flammable gases or fumes being present during this time is minimised.

1.3 General work area

The whole maintenance crew and other personnel at the site must be informed about

the nature of the works being performed. Work in tight areas must be prevented. The

area around the work site must be divided into sections. It must be ensured that the

conditions inside the area are safe by means of inspections of flammable materials.

1.4 Check for presence of arefrigerant

The area must be checked using an appropriate detector for the presence of refrigerant

before and during work to ensure that technicians are aware of apotentially flammable

atmosphere. It must be ensured that the device used for the detection of leaks is

suitable for use on flammable refrigerants, i.e. non-sparking, appropriately sealed or

intrinsically safe.

1.5 Presence of afire extinguisher

In the event that any work is performed on the cooling device or associated parts

under heat, then asuitable fire extinguisher must be on hand. In the vicinity of the

filling area, there must be apowder or CO2 fire extinguisher.

1.6 No ignition sources

No person performing work related to the cooling system that encompasses the

uncovering of any pipes that contain or have contained flammable gasses may

use any ignition sources in amanner that could lead to a fire or explosion hazard.

All possible ignition sources, including the smoking of cigarettes should be kept at

asufficient distance from the installation, repair, removal or disposal location, during

which flammable refrigerant could potentially be released into the surrounding

environment. Prior to starting work, the area around the appliance must be checked

to ensure that there are no fire hazards or ignition risks present. A"smoking forbidden"

sign must be installed.

1.7 Ventilated area

It must be ensured that the area is ventilated or appropriately ventilated prior to

penetrating the system or performing any work under heat. The intensity of ventilation

must continue for the time that works are performed. Ventilation should safely

dissipate any released refrigerant and draw it out into the atmosphere as apriority.

1.8 Cooling system checks

In places where electrical components are replaced, these components must be suitable

for this purpose and conform to correct specifications. The manufacturer'sinstructions

for maintenance and service must always be followed. If any doubts arise, it is

necessary to request help from the manufacturer'stechnical department.

On installations containing flammable refrigerants, it is necessary to perform the

following checks:

– the amount of refrigerant corresponds to the size of the room in which components

containing refrigerant are installed;

– ventilation systems and outlets are in full working order and are not clogged;

– if any indirect cooling circuit is used, the second circuit must be checked for the

presence of refrigerant;

– the markings on the appliance must remain constantly visible and legible, and

marking and signs that are illegible must be repaired;

– The cooling pipes and components are installed in locations where it is not probable

that they will be exposed to any substances that could corrode the parts containing

refrigerant, unless these components are built using materials that are inherently

resistant to corrosion or are appropriately protected against corrosion.

1.9 Electrical device check

The repair and maintenance of electrical components must include safety checks and

inspections of components.

In the event of a malfunction that could affect safety, no electrical power may be

connected to the circuit until the malfunction is satisfactorily resolved. In the event

that the malfunction cannot be immediately repaired but it is necessary to continue

running the appliance, an appropriate temporary solution must be used. The owner of

the appliance must be informed in such away that all parties know about it.

The initial safety check must ensure:

■ that capacitors are discharged: this must be performed in asafe way to prevent the

possibility of sparking;

■ that no electrical components or wiring is uncovered during the process of filling,

draining or cleaning the system;

■ that the grounding is not interrupted.

2. Repair of sealed components

When repairing sealed components, all the electrical power supply must be

disconnected from the appliance on which work is being performed before sealed

lids, etc. are removed. When it is absolutely necessary to have live power supply going

into the appliance while servicing the appliance, it is necessary to install apermanent

device in the most critical point to detect leakage so that a dangerous situation is

averted.

Special attention must be paid to ensuring that as aresult of the work performed on

electrical components the cover is not changed to the extent of affecting the level of

protection. This must also include damage to cables, excessive number of connections

and terminals not performed according to original specifications, damaged gaskets,

incorrect configuration of plugs, etc.

It is necessary to ensure that the appliance is mounted safely.

It is necessary to ensure that gaskets or sealing materials are not damaged in such

away that they no longer serve to prevent the entry of aflammable atmosphere. Spare

parts must conform to the manufacturer'sspecifications.

NOTE:

The use of silicone gaskets and seals may suppress the efficiency of

certain type of leak detection devices. Intrinsically safe components do

not need to be disconnected prior to being worked on.

3. Repairs of intrinsically safe components

No permanently inductive or capacitative load may be placed on the circuit without it

being ensured that thereby the permitted voltage and current for the used appliance

is not exceeded.

Intrinsically safe components are the only type on which it is possible to work in

aflammable environment even while under live current. Testing equipment must have

correct specifications.

Parts are replaced using only parts specified by the manufacturer. Different parts could

result in ignition of refrigerant upon leakage into the environment.

4. Cabling

Check that cabling is not exposed to wear and tear, corrosion, excessive pressure,

vibrations, sharp edges or any other negative environmental effects. This check must

also take into consideration the effects of ageing and permanent vibrations from

sources such as compressors or fans.

5. Detection of flammable refrigerants

Under no circumstances may potential sources of ignition be used for locating or

detecting refrigerant leaks.

Ahalogen burner (or any other type of detector utilising an open flame) must not be

used.

6. Leak detection methods

The following leak detection methods are considered acceptable for systems

containing flammable refrigerants.

For the detection of flammable refrigerants, electronic leak detectors must be used,

however their sensitivity may not be appropriate or they may require recalibration.

(Detection equipment must be calibrated in an area without any refrigerant present).

It is important to ensure that the detector is not apotential ignition source and that

it is suitable for the used refrigerant. The leak detector must be set to apercentage of

LFL refrigerant and must be calibrated for the used refrigerant and the respective gas

percentage is confirmed (maximum 25%).

Leak detection liquids are suitable for use on most refrigerants, however, detergents

containing chlorine must be excluded since chlorine may react with the refrigerant

and corrode copper pipes.

In the event of asuspected leak, all open flames must be removed/extinguished.

In the event that the refrigerant leak is found and requires hard soldering, then all

the refrigerant must be drained from the system or separated (by closing avalve) in

apart of the system distant from the leak. The system must then be cleaned out using

oxygen-free nitrogen (OFN) both before as well as after the hard soldering process.

7. Collection and pump discharge

In the event that the cooling circuit is breached due to repairs – or for any other reason

– conventional procedures must be followed. It is, however, important to adhere to the

best method due to flammability. It is necessary to adhere to the following procedure:

■ collect the refrigerant;

■ clean out the circuit using inert gas;

■ pump out;

■ again clean out using inert gas;

■ open the circuit by cutting or hard soldering.

The contents of the circuit must be collected into correct collection cylinders. The

system must be "flooded" with OFN (oxygen-free nitrogen) for the unit to remain

safe. It may be necessary to repeat the procedure several times. For this task, neither

compressed air nor oxygen may be used.

Flooding may be achieved by disrupting the vacuum in the system with the use of

OFN, and by continued filling until the operating pressure is achieved, then venting

into the atmosphere and finally lowering to avacuum. This process must be repeated if

refrigerant still remains in the system. When the last OFN cartridge is used, the system

must be ventilated to atmospheric pressure to enable work to be performed. This

activity is absolutely necessary if hard soldering is to be performed on the pipes.

It is necessary to ensure that the vacuum pump outlets are not nearby to any ignition

source, and ventilation must be provided.

8. Filling procedure

Apart from conventional filling procedures, also the following requirements must be

adhered to.

– It is necessary to ensure that no contamination by various refrigerants occurs when

the filling device is used. Hoses or pipes must be as short as possible to minimise the

amount of refrigerant contained inside of them.

– Cylinders must be held vertically.

– It is important to ensure that the cooling system is grounded prior to being filled

with refrigerant.

– When filling is complete, the system must be marked with alabel (if it does not have

one already).

– It is necessary to pay extreme care to ensure that the cooling system is not overfilled.

Apressure test using OFN must be performed before refilling the system. In the case

of a leak, the system must be tested after being refilled but also before being put

into operation. Averification test must be performed before leaving the installation

location.

9. Taking out of operation

Prior to performing this procedure it is essential that the technician fully acquaints

him/herself with the device and all its particulars. Correct practice of safely collecting

all refrigerant is recommended. Prior to performing this activity, oil and refrigerant

samples must be taken if an analysis is required prior to using the using the

regenerated refrigerant for the first time. It is essential that prior to starting this activity

that electricity is available.

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Sencor SDH 2020 Manual

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