1
1-11-2-1-5
• remove refrigerant -> • purge the circuit with inert gas -> • evacuate -> • purge with inert gas ->
• open the circuit by cutting or brazing
•
The refrigerant charge shall be recovered into the correct recovery cylinders.
•
The system shall be purged with OFN to render the appliance safe. (remark: OFN = oxygen free nitrogen, type of
inert gas)
•
This process may need to be repeated several times.
•
Compressed air or oxygen shall not be used for this task.
•
Purging shall be achieved by breaking the vacuum in the system with OFN and continuing to fi ll until the working
pressure is achieved, then venting to atmosphere, and fi nally pulling down to a vacuum.
•
This process shall be repeated until no refrigerant is within the system.
•
When the fi nal 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 potential ignition sources and there is ventilation available.
8.
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 over fi ll the refrigerating system.
•
Prior to recharging the system it shall be pressure tested with OFN (refer to #7).
•
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.
•
Electrostatic charge may accumulate and create a hazardous condition when charging and discharging the refrigerant.
To avoid fi re or explosion, dissipate static electricity during transfer by grounding and bonding containers and equipment
before charging/discharging.
9.
Decommissioning
•
Before carrying out this procedure, it is essential that the technician is completely familiar with the equipment and
all its details.
•
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 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.
d) Pump down refrigerant system, if possible.
f) Make sure that cylinder is situated on the scales
before recovery takes place.
g) Start the recovery machine and operate in
accordance with instructions.
h) Do not over fi ll 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 fi lled 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.
SM830283-00_欧州向け R32シングル36-71形TD&SM.indb 5 20/01/30 10:25:58
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