Mitsubishi Electric CITY MULTI PQRY-P200YMF-B Service Handbook page 93

4) Treatment of inverter and compressor troubles
If the compressor does not work when error codes 4210, 4240, 4310 or 4340 are detected, determine the point of
malfunction by following the steps in the LED monitor display and countermeasures depending on the check
code displayed, then perform the procedures below.
No. Check Item
How many hours was the
power kept on before
1
operation?
When it is restarted, does
2
the trouble reappear?
3
Run the heat source unit
with the wiring to the
compressor disconnected.
At this time, change SW1-1
on the INV board to ON.
Note) The terminals of the 3
disconnected wires should
be isolated from each other.
*1 [Cautions when measuring the voltage and current of the inverter's power circuit.]
Since the voltage and current on the inverter's power supply side and its output side do not have a sine waveform, the
measurement values will differ depending on the measuring instrument and the circuit measured.
In particular, as the inverter's output voltage has a pulse waveform, the output frequency also changes, so differences in
measurement values will be great depending on the measuring instrument.
1
When checking if the inverter's output voltage is unbalanced or not (relative comparison of the voltages between
each of the lines), if you are testing with a portable tester, be sure to use an analog tester.
Use a tester of a type which can be used to judge if the transistor module or diode module is faulty.
In particular, in cases where the inverter's output frequency is low, there are cases where the variations in measured
voltage values between the different wires will be great when a portable digital tester is used, when in actuality they
are virtually equal, and there is danger of judging that the inverter is faulty.
2 It is recommended when checking the inverter's output voltage values (when measuring absolute values), that, if a
measuring device for business frequencies is used, a rectified voltage meter (with a
Correct measurement values cannot be obtained with an ordinary portable tester. (either analog or digital)
Symptoms
1 If it was kept on for 12 hours or
longer as specified.
2 It was kept on for less than the
specified period.
1 The compressor stops and the
same error code is displayed.
1 The compressor stops and the
same error code is displayed.
2 If the inverter's output voltage is
output with good balance, *1.
3 If the balance in the inverter's
output voltage is not good or if the
inverter's output voltages are all 0 V
(a digital tester cannot be used) *1.
–90–
Treatment
Go to [2].
Go to [2] after keeping the power on for the
specified time.
Perform the check of wiring shown in the
explanation of each error code.
Check the transistor module is faulty. (Go to
"Individual Parts Failure Judgment Meth-
ods.")
Check the coil resistance and insulation
resistance of the compressor, and if it is
normal, run it again, and if the trouble occurs
again, replace the compressor.
* Insulation resistance :
Coil resistance :
Check the transistor module.
Judge that the transistor module is faulty.
(Go to "Individual Parts Failure Judgment
Methods.")
If the transistor module is normal, replace
the INV board, then perform this item again
with SW1-1 ON. If the problem is solved and
you connect the compressor again, turn
SW1-1 OFF again. Check the compressor's
coil resistance and insulation resistance.
symbol) be used.
2MΩ or more
0.359 ~ 0.716Ω