Hitachi RCI-3.0UFE1NH Installation & Maintenance Manual page 11

SAFETY PRECAUTIONS
• 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 (maximum 25%) is confirmed.
• Leak detection fluids 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 flames shall be removed/ extinguished.
• If a leakage of refrigerant which requires brazing is found, all of the refrigerant shall be recovered from the system, or
isolated (by means of shut off valves) in a part of the system remote from the leak.
• Oxygen free nitrogen (OFN) shall be purged through the system both before and during the brazing process.
12 Removal and evacuation
• 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 flammability 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 refrigerant charge shall be recovered into the correct recovery cylinders.
• The system shall be "flushed out" 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 working.
• 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 ventilation available.
13 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.
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- 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.
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- Prior to recharging the system pressure shall be 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.
14 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 that all refrigerants are recovered safely.
Prior to the task being carried out, an oil and refrigerant sample shall be taken in case that an analysis is required prior to the re-
use of recovered refrigerant. It is essential that electrical power is available before the task.
a. Become familiar with the equipment and its operation.
b. Isolate system electrically.
5 HO2019289HA