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Refrigerant detection
• On no account use possible sources of ignition for refrigerant detection or
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leak detection.
• Flame leak detectors or other detectors with open flames must not be used.
Leak detection
The following leak detection processes are suitable for systems with flammable
refrigerants:
Leak detection with electronic refrigerant detectors:
• Electronic refrigerant detectors may not have the required sensi- tivity or
may need to be calibrated to the relevant range. Carry out the calibration in
refrigerant-free surroundings.
• The refrigerant detector must be suitable for the R32 refriger- ant to be de-
tected.
• The refrigerant detector must not contain any potential sources of ignition.
• Calibrate the refrigerant detector to the refrigerant used. Set the response
threshold to < 3 g/a, suitable for propane.
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Leak detection with liquid leak detectors:
• Liquid leak detectors are suitable for use with most refrigerants.
! Please note
Liquid leak detectors containing chlorine may react with
the refrigerant. This could result in corrosion.
Do not use liquid leak detectors that contain chlorine.
Measures to take if a leak in the refrigerant circuit occurs:
• Immediately extinguish all open flames in the vicinity of the heat pump.
• If brazing/soldering work needs to be undertaken to remedy the leak, al-
ways extract all the refrigerant from the refrigerant circuit. Purge the site
to be brazed/soldered before and during the braz- ing/soldering work with
oxygen-free nitrogen.
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 pro-
cedure 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
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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 atmo-
sphere, 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 sys-
tem 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.
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.
Before recharging, the system shall be pressure tested with OFN. The system
should be leak tested after recharging but before commissioning. An additional
leak test must be performed before leaving the site.
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Picco R32
Air/Water heat pumps with axial fans
Completed
Notes
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