Infiniton PAC-BD12 Manual De Usuario página 26

Idiomas disponibles

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 continuing to fill until the

working pressure is achieved, then venting to atmosphere, and finally pulling down to a va-

cuum. 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 pres-

sure 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

that ventilation is available.

LEAK DETECTION METHODS

The following leak detection methods are deemed acceptable for systems containing flam-

mable 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 refrige-

rant 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 – co-

nventional procedures shall be used. However, for flammable refrigerants 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 with inert gas;

open the circuit by cutting or brazing.