The refrigerant charge shall be recovered into the correct recovery cylinders. For appliances containing flammable refrigerants, the system shall be purged with

oxygen-free nitrogen to render the appliance safe for flammable refrigerants . This process may need to be repeated several times . Compressed air or oxygen shall

not be used for purging refrigerant systems.

For appliances containing flammable refrigerants, refrigerants purging shall be achieved by breaking the vacuum in the system with oxygen-free nitrogen and continu-

ing to fili until the working pressure is achieved, then venting to atmosp here, and finally pulling down to a vacuum . This process shall be repeated until no refrigerant

is within the system. When the final oxygen-free nitrogen charge is used, the system shall be vented down to atmospheric pressure to enable work to ta ke piace. This

operation is absolutely vital if brazing operations on the pipe-work are to take piace.

Ensure that the outlet for the vacuum pump is not close to any potential ignition sources and that ventilation is available.

15) Charging procedures

In addition to conventional charging procedures, the following requirements shall be followed:

•

Ensure that contamination of different refrigerants does not occur when using charging equipment. Hoses or lines shall be as short as possible to minimize the

amount of refrigerant contained in them.

•

Cylinders shall be kept in an appropriate position according to the instructions.

•

Ensure that the refrigerating system is earthed prior to charging the system with refrigerant.

•

Label the system when charging is complete(if not already).

•

Extreme care shall be taken not to overfill the refrigerating system.

Prior to recharging the system it shall be pressure tested with OFN. The system shall be leak tested on completion of charging but prior to commissioning. A follow up

leak test shall be carried out prior to leaving the site.

16) Decommissioning

Before carrying out this procedure, it is essential that the technician is completely familiar with the equipment and all its detail. It is recommended good practice that

all refrigerants are recovered safely. Prior to the task being carried out, an oil and refrigerant sample shall be taken. In case analysis is required prior to re-use of

recovered refrigerant. It is essential that electrical power is available before the task is commenced.

a) Become familiar with the equipment and its operation.

b) Isolate system electrically

c) Before attempting the procedure ensure that:

•

Mechanical handling equipment is available, if required, for handling refrigerant cylinders;

•

All personal protetive equipment is available and being used correctly;

•

The recovery process is supervised at all times by a competent person;

•

Recovery equipment and cylinders conform to the appropriate standards.

d) Pump down refrigerant system, if possible.

e) If a vacuum is not possible, make a manifold so that refrigerant can be removed from various parts of the system.

f) Make sure that cylinder is situated on the scales before recovery takes place.

g) Start the recovery machine and operate in accordance with manufacturer s instructions.

h) Do not overfill cylinders. (No more than 80% volume liquid charge).

i) Do not exceed the maximum working pressure of the cylinder, even temporarily.

j) When the cylinders have been filled correctly and the process completed, make sure that the cylinders and the equipment are removed from site promptly and all

isolation valves on the equipment are closed off.

k) Recovered refrigerant shall not be charged into another refrigeration system unless it has been cleaned and checked.

17) Labelling

Equipment shall be labelled stating that it has been de-commissioned and emptied of refrigerant. The label shall be dated and signed. Ensure that there are labels on

the equipment stating the equipment contains flammable refrigerant.

18) Recovery

When removing refrigerant from a system, either for service or decommissioning, it is recommended good practice that all refrigerants are removed safely.

When tranferring refrigerant into cylinders, ensure that only appropriate refrigerant recovery cylinders are employed. Ensure that the correct numbers of cylinders for

holding the total system charge are available. All cylinders to be used are designated for the recovered refrigerant and labelled for that refrigerant(i.e special cylinders

for the recovery of refrigerant). Cylinders shall be complete with pressure relief valve and associated shut-off valves in good working order.

Empty recovery cylinders are evacuated and, if possible, cooled before recovery occurs.

The recovery equipment shall be in good working order with a set of instructions concerning the equipment that is at hand and shall be suitable for the recovery of

flammable refrigerants. In addition, a set of calibrated weighing scales shall be available and in good working order.

Hoses shall be complete with leak-free disconnect couplings and in good condition. Before using the recovery machine, check that it is in satisfactory working order,

has been properly maintained and that any associated electrical components are sealed to prevent ignition in the event of a refrigerant release. Consult manufacturer

if in doubt.

The recovered refrigerant shall be returned to the refrigerant supplier in the correct recovery cylinder, and the relevant Waste Transfer Note arranged. Do not mix

refrigerants in recovery units and especially not in cylinders.

If compressors or compressor oils are to be removed, ensure that they have been evacuated to an acceptable level to make certain that flammable refrigerant does

not remain within the lubricant. The evacuation process shall be carried out prior to retruning the compressor to the suppliers. Only electric heating to the compressor

body shall be employed to accelerate this process. When oil is drained from a system, it shall be carried out safely.

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

OMNIA ST 3.2

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