Coltech MDDE-10DEN3-QA3 - Page 8

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ENGLISH
Therefrigerant charge shall be recovered into thecorrect recovery cylinders.
Thesystem shall be flushed 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 achieved by breaking thevacuum in thesystem with OFN and
continuing to fill until theworking pressure is achieved, then venting to atmosphere,
and finally pulling down to avacuum.
This process shall be repeated until no refrigerant is within thesystem.
When thefinal OFN charge is used, thesystem shall be vented down to atmospheric
pressure to enable work to take place. This operation is absolutely vital if brazing
operations on thepipe-work are to take place. Ensure that theoutlet for thevacuum
pump is not close to any ignition sources and there is aventilation available.
16. 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 minimise
theamount of refrigerant contained in them.
• Cylinders shall be kept upright.
• Ensure that therefrigeration 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refrigeration 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.
17. 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 reclaimed 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 protective 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.