37MGHAQ: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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8. Checks to the refrigeration equipment
Where electrical components are being changed, they shall be fit for
the purpose and to the correct specification. At all times the
manufacturer’s maintenance and service guidelines shall be
followed. If in doubt consult the manufacturer’s technical
department for assistance. The following checks shall be applied to
installations using FLAMMABLE REFRIGERANTS:
• the actual refrigerant charge is in accordance with the room size
within which the refrigerant containing parts are installed;
• the ventilation machinery and outlets are operating adequately
and are not obstructed;
• if an indirect refrigerating circuit is being used, the secondary cir-
cuits shall be checked for the presence of refrigerant; marking to
the equipment continues to be visible and legible, marking and
signs that are illegible shall be corrected;
• refrigeration pipe or components are installed in a position where
they are unlikely to be exposed to any substance which may cor-
rode refrigerant containing components, unless the components
are constructed of materials which are inherently resistant to
being corroded or are suitably protected against being so cor-
roded.
9. Checks to electrical devices
Repair and maintenance to electrical components shall include initial
safety checks and component inspection procedures. If a fault exists
that could compromise safety, then no electrical supply shall be
connected to the circuit until it is satisfactorily dealt with. If the fault
cannot be corrected immediately but it is necessary to continue
operation, and adequate temporary solution shall be used. This shall
be reported to the owner of the equipment so all parties are advised.
Initial safety checks shall include:
• that capacitors are discharged: this shall be done in a safe manner
to avoid possibility of sparking
• that there no live electrical components and wiring are exposed
while charging,
• that there is continuity of earth bonding.
10. Sealed electrical components shall be replaced.
11. Intrinsically safe components must be replaced.
12. Cabling
Check that cabling will not be subject to wear, corrosion, excessive
pressure, vibration, sharp edges or any other adverse environmental
affects. The check shall also take into account the affects of aging or
continual vibration from sources such as compressors or fans.
13. Detection of flammable refrigerants
Under no circumstances shall potential sources of ignition be used in
the searching for or detection of refrigerant leaks. A halide torch (or
any other detector using a naked flame) shall not be used. The
following leak detection methods are deemed acceptable for
refrigerant systems. Electronic leak detectors may be used to detect
refrigerant leaks but, in the case of FLAMMABLE
REFRIGERANTS, 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 also 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.
NOTE: Examples of leak detection fluids are:
- bubble method,
- fluorescent method agents.
If a leak is suspected, all naked flames shall be removed/extin-
guished.
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. See
the following instructions of removal of refrigerant.
14. Removal and Evacuation
When breaking into the refrigerant circuit to make repairs - or for any
other purpose conventional procedures shall be used. However, for
flammable refrigerants it is important that best practice be followed, since
flammability is a consideration.
The following procedure shall be adhered to:
• safely remove refrigerant following local and national regulations;
• evacuate;
• purge the circuit with inert gas (optional for A2L);
• evacuate (optional for A2L);
• continuously flush or purge with inert gas when using flame to open
circuit; and
• open the circuit.
The refrigerant charge shall be recovered into the correct recovery
cylinders if venting is not allowed by local and national codes. For
appliances containing flammable refrigerants, the system shall be purged
with oxygen-free nitrogen to render the appliance safe for flammable
refrigerants. This process might 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 vacuum (optional for
A2L). This process shall be repeated until no refrigerant is within the
system (optional for A2L). When the final oxygen-free nitrogen charge is
used, the system shall be vented down to atmospheric pressure to enable
work to take place.
The outlet for the vacuum pump shall not be close to any potential
ignition sources, and ventilation shall be available.
15. Charging procedures
In addition to conventional charging procedures, the following
requirements shall be followed:
• Works shall be undertaken with appropriate tools only (In case of
uncertainty, please consult the manufacturer of the tools for use with
flammable refrigerants).
• 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 upright.
• 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.
• Prior to recharging the system it shall be pressure tested with oxygen
free nitrogen (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.
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