GREE ELECTRIC GUHD09NK3CO Service Manual page 117

3 Status Indicating Lamp of the Electric Control Box of the Outdoor Unit
2.2.2 Analysis to the Common After-Sales Faults
1. Stalling of the Outdoor Fan Motor
Method of testing the AC fan motor: pull out the terminals of the fan motor, then measure the resistance between
the red, brown, and black wires with the universal meter; the normal resistance is several hundreds ohms, if not, it
indicates there is a open circuit and the fan motor is defective.
If the measured resistance of the fan motor is abnormal, please replace the fan motor; if not, please replace the
control of the outdoor unit.
2. Temperature Sensing Fault
Replace the corresponding temperature sensor according to the error code. If possible, pull out the temperature
sensor and measure the resistance between its two ends to see if the it is defective or not.
If the fault still exists afte r the replacement of the temperature sensor, then please replace the electric control box
of the outdoor unit.
3. IPM Protection(H5)
a.Pull out the power plug for three minutes and then plug it again, in which case, if H5 appears in no time, check
if the terminals of the compressor are improperly connected or loosened; if not, replace the electric control box of the
outdoor unit; if the fault still exists, then it indicates the compressor is defective and should be replaced.
b. When H5 appears after the unit has run for a period of time, then it is necessary to see if the running
the wiring of the compressor is reverse, the screws of the module is tightened, or if the compressor is defective etc; If
the fault is beyond the statement above, please replace the electric control box of the outdoor unit.
4. Heating Failure
1. Under the heating status, measure the voltage between two wires of the four-way valve with a universal meter.
The testing points are 4V and AC-L2. If the measured voltage is not about AC230V, then it indicates that the electric
control box of the outdoor unit is defective and should be replaced.
2. If the measured voltage is about AC230V, then cut off the power supply and pull out these two wires of the four-
way valve and measure the resistance between the test points to see if it is about 1-2K. If it is much larger, it indicates
that there is a open circuit among the coils of the four-way valve which then should be replaced.
3. If the coils of the four-way valve is normal, then the failure may be caused by the system abnormity.
5. Cooling Failure
The cooling failure is posed generally when the Relay K5's contactor of the four-way valve of the outdoor unit's
electric control box is bonded, and it can be checked out by the universal meter.
2.2.3 Solutions to the Unsolved Faults after the Replacement of the Electric Control Box
1 .After the Replacement of the Electric Control Box of the Outdoor Unit
If the faults still exist after the replacement of the electric control box of the outdoor unit, please take a check to
see if the communication line, temperature sensor, reactor, fan motor, or compressor is normal or not.
Communication line: check if the communication line, live line, or neutral line are connected improperly or the
contactor of the terminals are not good. If the line is extended, then check if the joint is in good condition.
Temperature sensor: measure the grounding resistance between the points 3.3V and IPM15V (the testing method
is same as above); if the grounding is shortcut, please check if each temperature sensor is damaged or if there is arcing
trace on its outer housing or metal ends
Reactor: if the communication error remains after the replacement of the electric control box, then pull out the two
terminals of the reactor and measure the resistance between them with a universal meter; if the measure valve is about
several ohms, it indicates the terminals of the reactor is likely to break off.
Fan motor: pull out the terminals of the fan motor and measure the resistance between the red, brown and black
wires with a universal meter; The normal value is about several hundreds ohms, if the measure value is beyond this
range, it indicates there is a open circuit or the fan motor is defective.
Compressor: apart from the badly running environment, improper connection, or systematic abnormity, if H5
still occurs frequently after the replacement of the electric control box, then it indicates that the compressor is probably
defective.
U-Match Series DC
Inverter Service Manual
114