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• Reducing frequency – If [I frequency reducing phase current] ≤ I phase current < [I phase turn-off phase current],
the compressor shall continue to reduce frequency until the lowest frequency limit or out of the condition of
reducing frequency.
• Power turn-off – If [I phase current] ≥ [I power turn-off phase current], the compressor phase current shall stop
working for overcurrent protection, if [I phase current] ≤ [I frequency reducing phase current], and the compressor
have stopped working for 3 minutes, the machine shall be allowed to operate.
• If the overcurrent protection of compressor phase current continuously occurs for six times, it should not be
resumed automatically, and you should press the ON/OFF button to resume. During the process of running, if
the running time of compressor exceeds the [T clearing time of compressor phase current times], the overcurrent
protection is cleared to recount.
12. Starting-up Failure Protection for Compressor
a. Stop the compressor after its starting-up fails, restart it after 20 seconds if the fault does not show, and if they are all
failing for the successive start 3 time, it shall be reported as starting-up failure, and then restart after 3 minutes. When
it still not be able to operate through carry out the above process for 5 times, it is available if press ON/OFF. And the
compressor should be cleared the times after it run 2 minutes.
13. Out-of-Step Protection for Compressor
a. The out-of-step protection signal should be detected immediately after starting-up compressor, and once find the out-
of-step protection signal, the out-of-step protection shall be stopped, if it can run for lasting power turn-off 3 minutes,
the machine shall be allowed to operate. If it still can’t run automatically when the out-of-step protection for compres-
sor happens to stop working for 6 times in succession, it needs to press ON/OFF to operate. And if the running time is
more than 10 minutes, the power turn-off times for out-of-step protection shall be cleared and recounted.
14. Voltage Abnormality Protection for DC Bus
a. To detect voltage abnormality for DC bus after completing the pre-charge.
i. Over-high Voltage Protection for DC Bus: If it found the DC bus voltage UDC > [UDC Jiekuangchun protection],
turn off PFC and stop the compressor at once, and it shall show the DC over-high voltage failure, it should clear out
the failure when the voltage dropped to UDC < [UDC Jiekuangchun recovery] and the compressor stopped for 3
minutes.
ii. Over-low Voltage Protection for DC Bus: If it found the DC bus voltage UDC < [UDC Jiekuangchun protection],
turn off PFC and stop the compressor at once, and it shall show the DC over-low voltage, and it should clear out the
failure when the voltage is raised UDC > [UDC Wantuochun recovery] and the compressor stopped for 3 minutes.
iii. To Detect Voltage Abnormality Protect for DC Bus When Getting Electricity: If it found the DC bus voltage UDC >
[UD over-high voltage], turn off the relay at once, and shows voltage abnormality failure for DC bus. And the failure
cannot recover except to break-off and get the electricity.
b. Abnormality Protection for Four-Way Valve
i. Under the model of heating operation in good condition, the compressor is detected [T inner pipe < (T inner ring –T
abnormality temperature difference for four-way valve reversion)], during the running, it should be regarded as four-
way valve reversion abnormality. And then it can run if stop the reversion abnormality protection for four-way valve
3 minutes, and if it still cannot run when the reversion abnormality protection for four-way valve happens to stop
working for 3 times in succession it is available for ON/OFF.
ii. Attention: the protection shall be shielded during the testing mode and defrosting process, and it shall be cleared
out the failure and its times immediately when turning off or delivering wind/cooling/dehumidifying mode conversed
(the inverted mode does not clear out the failure when it cannot recover to operate).
c. PFC Protection
i. After you start the PFC, it should detect the protection signal of the PFC immediately. Under the condition of PFC
protection, it should turn-off the PFC and compressor at one time.
ii. It shows the failure is cleared out if PFC protection stopped working 3 minutes and recovers to run automatically.
iii. If it still cannot run when it occurs PFC protection for 3 times in succession, it is available if presses ON/OFF and
clear the PFC protection times when start-up PFC from 10 minutes.
d. Failure Detection for Sensor
i. Outdoor Ambient Sensor
1. Detects the failure of sensor at all times.
ii. Outdoor Tube Sensor
1. You should not detect the failure of outdoor tube sensor within 10 minutes heating operation compressor except
the defrosting and you could detect it at other times.
iii. Outdoor Exhaust Sensor
1. The compressor only detects the sensor failure after it starts for 3 minutes in normal mode.
2. It should detect the exhaust sensor failure immediately in the testing mode.
