51
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27
）
Function protection prompt of frequency conversion external machine
Explanation of
error
Cause:
In the regular running of the air conditioner, for some
nonfaulted status, it may need the compressor to shut down or limit or
lower the frequency so as to protect the normal operating of the entire
cooling system (eg. defrosting, slight undercooling, over pressure,
overcurrent, etc.). These problems are not considered as errors and
would not be reflected in the internal machine, however as to make
sure the maintenance personnel is familar with the running status of the
air conditioner, three indicator lights are used on the main external
control panel for reference of the maintenance personnel.
Including:
over current protection, cooling overload protection, indoor
heating high temperature protection, indoor cooling freezing
protection, over pressure and under pressure protection.
Tools required
for inspection
Multimeter.
Frequent
problematic part
Regular protection, system blockage, power supply not as usual,
resistance value of sensor drifts or is used wrong.
Inspection
procedure and
key points
1.
Defrosting: with a defrosting signal, meaning the air conditioner is
under defrosting procedure and it is normal, but if there is frequent
defrosting, it shall be specifically noted if heat exchange of the external
unit is faulted, if the fan revolving speed is low and if the resistance
value of the coil sensor is drifted or the temperature is inaccurately
measured or it is damaged.
2.
Over current protection: it is more possible to appear under high
temperature cooling status and the over current of compressor is
usually reflected by over high load of the compressor. It is normal if
such protection appears under a very high temperature cooling status
but not under low temperature low load status.
3.
Cooling overload protection: it is more possible when the frequency
conversion machine is under a high temperature cooling status. When
the outdoor coil sensor senses the temperature is too high, as to provent
the compressor from overload, it would possitively lower the
frequency and it is normal for the protection under the high
temperature cooling status.
4.
Indoor high temperature heating protection: it is more possible when
the frequency conversion machine is under a high temperature heating
status. When the indoor coil sensor senses the temperature is too high,
as to provent the compressor from overload, it would possitively lower
the frequency and it is normal for the protection in a warm room.
5.
Indoor cooling freezing protection: it is more possible to appear
under a low temperature cooling status. When the indoor coil sensor
senses the temperature is too low, as to prevent the heat exchanger of
the internal machine from frosting, it would possitively lower the
frequency and it is normal for the protection in a low temperature
room.
