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High and low pressure protection
a) This protection is to guarantee the unit runs in allowing range, free from the compressor damage
b) High pressure protection: High pressure switch off and lasts for 3s, high pressure protection appears, the compressor and fan
motor all stops, alarm outdoor unit protection, and failure code will not disappear even when high pressure switch returns to
normal, but the unit can resume when restart.
c) Low pressure protection
① Checking low pressure failure after the unit starts for 5 min, low pressure switch off and lasts for 3s, low pressure protection
appears, the compressor and fan motor stop, alarming outdoor protection,
failure code disappear after low pressure switch return to normal, when the compressor 3 min protection is satisfied unit returns
to normal running.
②When low pressure appears 3 times in 30 min, the protection is unable to resume, the whole unit stops and the unit can
resume after the failure is solved and restart
③Do not check low pressure when defrosting.
Note: This function is available for three phase power supply
Phase sequence protection
a) This protection is to prevent the compressor rollback or lack phase lead to over current, and finally destroy the compressor
b) When outdoor unit appears lack phase or phase sequence incorrect, the unit stops immediately and enters into protection,
alarming outdoor protection, even phase sequence or lack phase switch return to normal the failure code will not disappear, the unit
can resume when restarting
Outdoor fan motor control
The unit has function of low ambient cooling and high ambient heating, when cooling take outdoor coil temperature as basis and
when heating take indoor coil temperature as basis, the outdoor fan automatic carries out stepless speed adjustment to keep the
unit in normal operation state.
Defrosting control
a)
On the situation that the outdoor sensor is in good condition, once following conditions are satisfied defrosting begins, the
operation lamp will shine when running defrosting.
① Outdoor coil temperature below definite temperature and lasts for 2 min
②The compressor running time surpass defrosting internal time (defrosting internal time recalculates when power off by
accident or remote controller), the compressor keeps running continuously for over 5
min. When defrosting begins, the compressor, indoor fan, outdoor fan will stop, 15s later 4-way valve will be closed, and 5
more seconds later the compressor enters into defrosting operation.
b)
Ending defrosting condition (one of the following conditions is satisfied defrosting ends)
① Outdoor coil temperature ≥12℃
② Defrosting time up to 10 min
③ Mode switch or turning off the unit by remote controller defrosting exits immediately.
CONTROL SYSTEM
23 | S e r v i c e M a n u a l
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