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11. Technical information.
11.1 Operating principle.
The cooling unit for electric enclosures works
on
the
basis
of
a
refrigeration
consisting
of
four
main
compressor,
evaporator,
condenser
expansion device (figure F.36.0). The circuit is
hermetically
sealed
and
circulates inside it. The refrigerant used is
R134a, chlorine free and harmless for the
ozone layer. The unit is divided into two
hermetically separated sections where the
ambient air and enclosure air do not come
into contact with one another and are treated
separately. The compressor (CP) compresses
the refrigerant and takes it to a high pressure
and high temperature. The compressor then
pushes
the
refrigerant
through
12. Troubleshooting
Malfunction
It fails to cool
It is not cooling enough
Too much condensate forming
exchanger coil, called condenser (C), where it
is cooled by ambient air thus passing from the
gas to the liquid state. At the liquid state it
circuit
then passes through the capillary (EXP) and
components:
as it is at a much lower pressure, nebulizes at
and
the outlet. It is then received by the heat
exchanger coil, called evaporator (E), by
the
refrigerant
means of which it absorbs heat from the
enclosure air and passes from a liquid state to
gas. The enclosure is cooled down in this
manner. The gas is then drawn back into the
compressor and the above described cycle is
repeated.
11.2 Safety devices.
The refrigeration circuit is fitted with a high
pressure safety switch P (figure F.36.0) set at
a
heat
maximum cooling unit working pressure. If the
Conditions
The internal fan works, the external fan and
compressor do not work.
No component works
Compressor, external and internal fan work
Compressor and external fan work, internal
fan does not work
External and internal fan work, compressor
does not work
External and internal fans work, com-
pressor works all the time
Inside fan works, external fan and com-
pressor work irregularly
External and internal fans work, com-
pressor works irregularly
Enclosure door open
Enclosure door closed
Causes
The temperature inside the enclosure is lower than
what is set on the adjustment thermostat.
The adjustment thermostat has failed
No electricity getting to the unit.
Cooling unit empty of fluid
Compressor mechanical failure
Internal fan capacitor failed
Internal fan failed
Compressor's amperometric protector failed (ex-
ternal to the compressor, where present)
Relay or PTC for compressor starting failed
Capacitor for compressor starting failed (where pre-
sent)
Compressor motor electrical failure
High pressure safety switch failed
Compressor contactor failed (where present)
Cooling unit under sized for the heat dissipated
inside the enclosure
Insufficient gas in the cooling unit
High pressure safety switch triggered:
Ambient temperature over the maximum
working limit
Heat exchanger coil (condenser) either dirty
or clogged
Thermal protector inside the compressor triggered:
Ambient temperature over the maximum
working limit
Heat exchanger coil (condenser) either dirty
or clogged
Too much ambient air inside the enclosure
Enclosure protection level is below IP54
The enclosure/cooling unit connecting seal has
been fitted incorrectly
threshold is exceeded, the pressure switch
stops the compressor working. It is the auto-
matically resettable type. The fans and com-
pressor have a thermal cut-out switch inside
that stops them in the case of anomalous over
temperatures.
11.3 Disposal.
Caution! The cooling unit contains R134a
refrigerant
and
small
lubricating oil. These substances pollute and
must not be dumped. Replacement, repairs
and final disposal must be seen to by experts.
NOTE
Keep the documentation in a dry place.
Remedy
This is not a malfunction of the cooling unit. To verify functioning
when testing, lower the thermostat setting until the compressor
and external fan start working and then reset the thermostat.
Change the adjustment thermostat
This is not a malfunction of the cooling unit.
Make sure the power cable has been connected well to
the terminals.
Check that the cubicle doors and switches are closed
Call a refrigeration expert or the Manufacturer's Technical
Assistance Service
Call a refrigeration expert or the Manufacturer's Technical
Assistance Service
Change the internal fan's capacitor
Change the internal fan
Change the amperometric protector
Change the relay or PTC for compressor starting
Change the capacitor for compressor starting
Call a refrigeration expert or the Manufacturer's Technical
Assistance Service
Call a refrigeration expert or the Manufacturer's Technical
Assistance Service
Change the contactor
Change the cooling unit with another of greater capacity
Call a refrigeration expert or the Manufacturer's Technical
Assistance Service
Ventilate the premises where the enclosure is installed
to keep ambient temperature lower.
Clean the exchanger with compressed air and detergent
Ventilate the premises where the enclosure is installed
to keep ambient temperature lower.
Clean the coil with compressed air and detergent
This is not a malfunction of the cooling unit. Close the enclosure
door or disable the cooling unit
This is not a malfunction of the cooling unit. Seal enclosure
openings, e.g. for passage and upward path of wires
Check seal and remedy
quantities
of
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