
14 / EN Local air-conditioner / User Manual
that ths wll not exceed the permssble voltage
and current permtted for the equpment n use.
Intrnscally safe components are the only types
that can be worked on whle lve n the presence
of a flammable atmosphere. The test apparatus
shall be at the correct ratng. Replace components
only wth parts specfed by the manufacturer.
Other parts may result n the gnton of
refrgerant n the atmosphere from a leak.
2.4 Cablng
Check that cablng wll not be subject to wear,
corroson, excessve pressure, vbraton, sharp
edges or any other adverse envronmental
effects. The check shall also take nto account
the effects of agng or contnual vbraton from
sources such as compressors or fans.
2.5 Detecton of flammable
refrgerants
Under no crcumstances shall potental sources of
gnton be used n the searchng for or detecton
of refrgerant leaks. A halde torch (or any other
detector usng a naked flame) shall not be used.
2.6 Leak detecton methods
The followng leak detecton methods are
deemed acceptable for systems contanng
flammable refrgerants. Electronc leak detectors
shall be used to detect flammable refrgerants,
but the senstvty may not be adequate, or may
need recalbraton. (Detecton equpment shall
be calbrated n a refrgerant-free area.) Ensure
that the detector s not a potental source of
gnton and s sutable for the refrgerant used.
Leak detecton equpment shall be set at a
percentage of the LFL of the refrgerant and shall
be calbrated to the refrgerant employed and the
approprate percentage of gas (25 % maxmum)
s confrmed. Leak detecton fluds are sutable
for use wth most refrgerants but the use of
detergents contanng chlorne shall be avoded
as the chlorne may react wth the refrgerant
and corrode the copper ppe-work. If a leak s
suspected, all naked flames shall be removed/
extngushed. If a leakage of refrgerant s found
whch requres brazng, all of the refrgerant shall
be recovered from the system, or solated (by
means of shut off valves) n a part of the system
remote from the leak. Oxygen free ntrogen (OFN)
shall then be purged through the system both
before and durng the brazng process.
2.7 Removal and evacuaton
When breakng nto the refrgerant crcut to make
repars – or for any other purpose – con-ventonal
procedures shall be used.However, t s mportant
that best practce s followed snce flammablty
s a consderaton. The followng procedure shall
be adhered to: remove refrgerant; purge the
crcut wth nert gas; evacuate; purge agan wth
nert gas; open the crcut by cuttng or brazng.
The refrgerant charge shall be recovered nto
the correct recovery cylnders. The system shall
be “flushed” wth OFN to render the unt safe.
Ths process may need to be repeated several
tmes.Compressed ar or oxygen shall not be
used for ths task. Flushng shall be acheved by
breakng the vacuum n the system wth OFN and
contnung to fll untl the workng pressure s
acheved, then ventng to atmosphere, and fnally
pullng down to a vacuum. Ths process shall be
repeated untl no refrgerant s wthn the system.
When the fnal OFN charge s used, the system
shall be vented down to atmospherc pressure
to enable work to take place.Ths operaton s
absolutely vtal f brazng operatons on the
ppework are to take place.
2. Instructons for reparng applances contanng
R290