ACD-18KBTU
The following checks shall be applied to installations
using ammable refrigerants:
-- The charge size 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 circuit shall be checked for the
presence of refrigerant;
-- Marking to the equipment continues to be
visible and legible. Markings 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 corrode refrigerant
containing components, unless the components
are constructed of materials which are inherently
resistant to being corroded or are suitably
protected against being so corroded.
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, an
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, recovering
or purging the system;
-- That there is continuity of earth bonding.
Repairs to sealed components
During repairs to sealed components, all electrical
supplies shall be disconnected from the equipment
being worked upon prior to any removal of sealed
covers, etc. If it is absolutely necessary to have an
electrical supply to equipment during servicing,
then a permanently operating form of leak
detection shall be located at the most critical point
to warn of a potentially hazardous situation.
Particular attention shall be paid to the following
to ensure that by working on electrical components,
the casing is not altered in such a way that the level
of protection is affected. This shall include damage
to cables, excessive number of connections,
terminals not made to original specication,
damage to seals, incorrect tting of glands, etc.
Ensure that apparatus is mounted securely. Ensure
that seals or sealing materials have not degraded
such that they no longer serve the purpose of
preventing the ingress of ammable atmospheres.
Replacement parts shall be in accordance with the
manufacturer's specications.
NOTE: The use of silicon sealant may inhibit the
effectiveness of some types of leak detection
equipment. Intrinsically safe components do not
have to be isolated prior to working on them.
Repair to intrinsically safe components
Do not apply any permanent inductive or
capacitance loads to the circuit without ensuring
that this will not exceed the permissible voltage and
current permitted for the equipment in use.
Intrinsically safe components are the only types
that can be worked on while live in the presence of
a ammable atmosphere. The test apparatus shall
be at the correct rating. Replace components only
with parts specied by the manufacturer. Other
parts may result in the ignition of refrigerant in the
atmosphere from a leak.
Check that cabling will not be subject to wear,
corrosion, excessive pressure, vibration, sharp
edges or any other adverse environmental effects.
The check shall also take into account the effects of
aging or continual vibration from sources such as
compressors or fans.
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 ame) shall not be used.
The following leak detection methods are deemed
acceptable for systems containing ammable
refrigerants.
Electronic leak detectors shall be used to detect
ammable 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 conrmed. Leak detection uids 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
ames 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 inammability
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.