Haier 1U18TR4ERA, Service Manual

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Functions and control
1
8
Domestic air conditioner
7.1.4 Four way control
For the details of defrosting four-way valve control, see the defrosting process.
Four way working in other ways:
Under the mode of heating, open the four-way valve, when the compressor is not started or
changed to non-heating mode, make sure the compressor is stoped for 2 minutes, and then close the
four-way valve.
7.1.5 Protection function
7.1.5.1 TTC high temperature-preventing protection
Once the machine is started, it can run TTC(air-blowing temp) overheating protection of
air-blowing, but air-blowing sensor malfunction must alarm after 4 minutes during which the
compressor is started (during the course of self-detection, there’s no such limitation)
Sensor detection methods: 100 times (one cycle of procedure run is one time, and about 5ms,
detection method for each time: continuously sampling for 8 times, then order them and take the mean
value of the middle 2 values), take the mean value.
TTC
（℃）
Abnormal stop
110
Decreasing the frequency rapidly
（
1HZ/second
）
100
Decreasing the frequency slowly (1HZ/10seconds)
98
The frequency doesn’t change.
93
Increasing the frequency (1HZ/10second)
90
Increasing the frequency
（ 1HZ/1second ）
TTC>=110
℃
lasts for 20 seconds. Overheating protection of air-blowing, alarm malfunction to the
indoor, others don’t last.
7.1.5.2 TC high temperature-preventing control of the indoor heating unit
：
Tpg_indoor is the highest value of the effective indoor unit (start it and it is in accord with the
running state). TC=indoor coil temp.
The indoor heat exchanger sensor tests the temperature of the indoor heat exchanger. If the
temperature is higher than 55
℃
, decrease the rotate speed of the compressor and do the high
temperature-preventing protection of the indoor heat exchanger; if the temperature of the indoor heat
exchanger is lower than 47
℃
, recover to the normal control.