evoheat Fusion-i 12, Руководство по установке и эксплуатации, Страница: 27 / 29

26 EvoHeat Fusion-i Series Manual
LEAK DETECTION METHODS
The following leak detection methods are deemed acceptable for systems containing flammable refrigerants.
Electronic leak detectors shall be used to detect flammable refrigerants, but the sensitivity may not be adequate, or
may need re-calibration. (Detection equipment shall be calibrated in a refrigerant-free area.) Ensure that the
detector is not a potential source of ignition and is suitable for the refrigerant used. 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 (25 % maximum) 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 is found which requires brazing, 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 then be purged through the system both before and during the brazing process.
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" 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 ventilation available.
working on them.
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.
RECOVERY
When removing refrigerant from a system, either for servicing or decommissioning, it is recommended good practice
that all refrigerants are removed safely.
When transferring refrigerant into cylinders, ensure that only appropriate refrigerant recovery cylinders are
employed. Ensure that the correct number of cylinders for holding the total system charge is 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.