F4- Exhaust Sensor Error - Toyotomi KURO Mini Service Manual

(12) F4- Exhaust sensor error

Cause: The main external control panel will indicate "exhaust sensor
error" and send it to the main internal control panel when it detects
Explanation of
short circuit or open circuit of the exhaust sensor.
error
Inspection path: Exhaust sensor→Sensor wire→Connectors→Main
external control panel
Tools required
Multimeter, 50KΩ standard exhaust sensor (25℃)
for inspection
Frequent
Exhaust sensor, main external control panel
problematic part
1. Check if there is any evident resistance problem in the sensor.
Whether in short circuit or open circuit, the resistance should maintain
in a reasonable range (about 50KΩ when the compressor is not
working and between 3 KΩ and 30 KΩ after the compressor works for
a while, the corresponding exhaust temperature should be 100 ℃
-38℃).
2. Check if the sensor wire or the sensor connecting wire is damaged.
3. Check if the connecting terminal is connected firmly, the weld
Inspection
between the terminal and the main control panel is loose; pull the
procedure and
terminal slightly for inspection if necessary.
key points
4. Check whether the sensor is affected with damp. The coil sensor is
quite easy to be affected with damp in case the lead wire of coil sensor
is above the copper pipe.
5. If there is no standard sensor at hand, exchange the exhaust sensor
with the one beside it to see if the error changes. If yes, there is
something wrong with the sensor and it should be replaced; if it still
indicates "external coil sensor error", replace the main external control
panel.
Most exhaust sensors have a standard resistance of 50KΩ (25℃). Do
not use improper sensor during maintenance, or the machine will sense
the exhaust temperature mistakenly and enters the protection state
frequently. For example, in the case where replace the 20KΩ coil
sensor for the exhaust sensor by mistake, the exhaust temperature that
Special attention
the main external control panel senses will be higher than the actual
exhaust temperature, which will make normal air conditioners enter the
high exhaust temperature protection state frequently, and the
compressor frequency threshold will rise and lead to shutdown of the
compressor.
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