5
The calibration of a valve that has leaked is generally
lower than its original calibration. The new calibration may
affect the operating range. To avoid a nuisance tripping or
leaks, replace or re-calibrate the valve.
Periodic check of the relief valves: See paragraph
“Maintenance safety considerations”. Provide a drain in
the discharge circuit, close to each relief valve, to avoid an
accumulation of condensate or rain water.
Ensure good ventilation, as accumulation of refrigerant in
an enclosed space can displace oxygen and cause
asphyxiation or explosions.
Inhalation of high concentrations of vapour is harmful and
may cause heart irregularities, unconsciousness, or death.
Vapour is heavier than air and reduces the amount of
oxygen available for breathing. These products cause eye
and skin irritation. Decomposition products are hazardous.
1.2 - Equipment and components under pressure
The units are intended to be stored and operate in an
environment where the ambient temperature must not be
less than the lowest allowable temperature indicated on
the nameplate. See section “Pressure vessels”.
1.3 - Maintenance safety considerations
The owner / operator shall keep an updated logbook of the
refrigerating system.
In the logbook the following information shall be
recorded:
•
details of all maintenance and repair work;
•
quantities and kind of (new, reused or recycled)
refrigerant which have been charged on each
occasion, and the quantities of refrigerant which have
been transferred from the system on each occasion;
•
analysis of a reused refrigerant, if available, the results
of which shall also be kept in the log-book;
•
source of the reused refrigerant;
•
changes and replacements of components of the
system;
•
results of all periodic routine tests;
•
record of significant periods of non-use.
The log-book shall either be kept by the owner / operator,
or the data shall be stored in a computer, in which case the
information shall be accessible to the competent person
when servicing or testing.
Engineers working on the electric or refrigeration compo-
nents must be authorized, trained and fully qualified to do so.
All refrigerant circuit work must be carried out by a
trained person, fully qualified to work on these units. He/
she must have been trained and be familiar with the
equipment and the installation. All welding operations
must be carried out by qualified specialists.
Before opening a refrigerant circuit, purge and consult the
pressure gauges. Reclaim the refrigerant using a proper
refrigerant reclaim device and reclaim cylinders.
The units can also be lifted with slings, using only the
designated lifting points marked on the unit.
Use slings with the correct capacity, and always follow
the lifting instructions on the certified drawings supplied
with the unit.
Safety is only guaranteed, if these instructions are carefully
followed. If this is not the case, there is a risk of failure
and injuries to personnel.
DO NOT COVER ANY PROTECTION DEVICES. This
applies to the relief valves (if used) in the refrigerant or
heat transfer medium circuits, the fuse plugs and the
pressure switches.
The external relief valves are designed and installed to
ensure damage limitation in case of a fire. In accordance
with the regulations applied for the design, the European
directive on equipment under pressure and in accordance
with the national usage regulations:
•
These relief valves (and rupture disk if used) are not
safety accessories but damage limitation accessories in
case of a fire,
•
The high pressure switches are the safety accessories.
The relief valve must only be removed if the fire risk is
fully controlled and after checking that this is allowed by
local regulations and authorities. This is the responsibility
of the operator.
When the unit is subjected to fire, safety devices prevent
rupture due to over-pressure by releasing refrigerant. The
fluid may then be decomposed into toxic residues when
subjected to the flame:
•
Stay away from the unit
•
Set up warnings and recommendations for personnel
in charge to stop the fire.
•
Fire extinguishers appropriate to the system and the
refrigerant type must be easily accessible.
The external relief valves must be connected to discharge
pipes for units installed in a room. Refer to the installation
regulations, for example those of European standards EN-378.
These standards include a sizing method and examples for
configuration and calculation. Under certain conditions
they permit connection of several valves to the same
discharge pipe.
These pipes must be installed in a way that ensures that
people and property are not exposed to refrigerant leaks.
These fluids may be diffused in the air, but far away from
any building air intake, or they must be discharged in a
quantity that is appropriate for a suitably absorbing
environment (Note that the R1234ze(E) refrigerant is
heavier than air).
It is recommended to install an indicating device to show if
part of the refrigerant has leaked from the valve. The
presence of oil at the outlet orifice is a useful indicator that
refrigerant has leaked. Keep this orifice clean to ensure
that any leaks are obvious.
