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9. Fan motor lock
Condensing fan motor lock can be detected by current in condensing fan motor A/B.
(1) Case-1: Diagnosis is performed by measuring the difference in current between condensing fan motor A
and B.
㽲 Diagnosed values in both current transformer A and B is decided after 2 minutes have elapsed since the
power was supplied.
Divide the diagnosed value in current transformer A into the diagnosed value in current transformer B.
㽳 If the difference between them deviates by more than 㫧15%, it is determained as “Fan motor locked” in
either condensing fan motor A or B. (Criterion: Value in current transformer A / value in current
transformer B = +/- 15%)
㽴 If unit continues the status of 㽳 for more than 5 minutes, it is diagnosed as abnormal.
㽵 If unit is diagnosed as an abnormal, fan motor protection (*1) activates.
㽶 For the prevention of misdiagnosis, condensing fan motor relay is forced to activate after 1 hour has
elapsed since an error occured 㽴 to check diagnosed value.
If there are no differences between diagnosed value in current transformer A and B, the error will be
eliminated and unit returns to normal operation.
If the unit detects an error for twice, it will stop checking diagnosed values anymore.
The unit will determine an error and failed condensing fan motor will turn off.
(2) Case-2: When both condensing fan motor A and B turn on and currents in fan motors A and B do not
increase if a unit commands both of fan motors to turn on, the unit gives an error immediately.
㽲 When both condensing fan motor A and B turn on after 2 minutes have elapsed since the power was
supplied, currents in both fan motor A and B are monitored continuously.
㽳 An error occurs immediately when both values in current transformer A and B are lower than 20 with
both fan motor A and B activate.
(3) Case-3: When either condensing fan motor A or B turns on and a current in the fan motor does not increase
when the unit commands the fan motor to turn on, the unit gives an error immediately.
㽲 It takes 2 minutes to start diagnosis after either condensing fan motor A or B are turned on.
㽳 An error occurs immediately when a value in current transformer A or B are lower than 20.
(4) Case-4: When either condensing fan motor A or B turns on and the temperature in either compressor A or B
is higher than 55㷄, a unit triggers an error.
㽲 The unit commands both condensing fan motors A and B to turn on.
㽳 If both condensing fan motors A and B activate, unit will perform diagnosis of Case-1 or Case-2.
If the diagnose value deviates from criterion, an error occurs.
If currents in fan motor A and B do not increase, an error occurs.
(*1) Fan motor protection: Failed fan motor relay turns off. (Compressors are controlled normally)
Buzzer sounds intermittently, error message will be displayed including time of
occurrance and remote alarm activates.
Error will be eliminated in the following condition;
1) When current is detected correctly after a condensing fan motor was replaced.
(It is necessary to reset fan motor accumulating time after replacement)
2) If diagnosis is performed twice and it is not detected an abnormal, unit determines a
misjudgement and returns to normal operation.
Error message will not be eliminated.
Buzzer stops sounding by pressing BUZZER key. (Ring back activates)
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