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SWIMMING POOL HEAT PUMP TYPE PV
Repairs to sealed components
1 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 detec-
tion shall be located at the most critical point to
warn of a potentially hazardous situation.
2 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 connec-
tions, terminals not made to original specification,
damage to seals, incorrect fitting 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 flammable atmospheres.
Replacement parts shall be in accordance with the
manufacturer's specifications.
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 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 flammable atmosphere. The test
apparatus shall be at the correct rating. Replace com-
ponents only with parts specified by the manufacturer.
Other parts may result in the ignition of refrigerant in
the atmosphere from a leak.
Cabling
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.
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.
Alterations which serve the technological progress as well as errors excepted!
Leak detection methods
The following leak detection methods are deemed
acceptable for systems containing flammable re-
frigerants. 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.
ORIGINAL MANUAL NORSUP
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