w w w . i n n o v a i r . c o m
DELUXE
Inverter
Service
M
anual
（
19
）
Function protection prompt of frequency conversion external machine
Explanation of
error
Cause:
During
the regular
functioni
ng 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 operati
on
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
.
To
make sure the
maintenance personnel is familar with the
functio
ning status of the air conditioner,
three indicator lights are used on the main external control panel
as
a
reference.
Including:
overcurrent protection, cooling overload protection, indoor heating high
temperature protection, indoor cooling freezing protection, overpressure 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:
it means the air conditioner is running a defrosting process that is normal
and it shows the defrosting signal. If
there is frequent defrosting, it shall be
specifically
noted if heat exchange of the external unit is fault
y
, 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. Overcurrent protection: it is more
proba
ble to appear under
high temperature cooling
status and the overcurrent 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
can possibly happen
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 pr
e
vent the compressor from overload,
it would
definit
ely lower the frequency and it is normal for the protection under the
high
temperature cooling status.
4. Indoor high temperature heating protection: it is
most probable
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 pr
e
vent the compressor from overload,
it would
most sur
ely lower the frequency and it is normal for the protection in a warm
room.
5. Indoor cooling freezing protection: it
could
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
. I
t would
positively
lower the frequency and it is normal for the protection in a low temperature
room.
6. Over or underpressure protection: this protection is a pilot protection for the "over
or under
-
pressure error". When the power pressure is too high or too low but not so
high or so low to reach limit for shutting down (within 165V-265V), it would limit
and
lower the frequency first to reduce the air conditioner's needs for the power to
keep t
h
e
air conditioner running. This protection is
to
adapt to a
n
unstable power
environment and when there is such protection prompt, it usually means it is possible
for "OVP and UVP error".
7. Cooling overload protection, indoor high temperature heating protection and indoor
coolign freezing protection are possibl
y
related to the drift of the resistance value
of
the sensor.
42
