Mitsubishi Electric CAHV-R450YA-HPB Service Manual page 160

[ X Troubleshooting ]
[4] Put the outdoor unit into oper-
Check whether ation.
the inverter is Check the inverter output volt-
damaged. age after the inverter output
(During com- frequency has stabilized.
pressor opera-
tion)
[5] Remove the wire for the out-
Check the fan door fan motor, and check the
motor ground fan motor megger and the
fault or the winding resistance.
winding.
[6] (1)
Check the fan
inverter board
failure.
(2)
[7] (1)
Check whether
the Fan Board
Detection Cir-
cuit at No
(2)
Load.
(3)
(4)
HWE22020
Items to be checked
Check the fan output wir-
ing.
Check the connector
CNDCP and CNDCN
connection.
Stop the unit.
Turn off the breaker.
*Be sure to turn off the
power.
To allow for the discon-
nection of output wiring
from the fan motor, dis-
connect connector
CNINV. (CNINV1 corre-
sponds to the left fan and
CNINV2 corresponds to
the right fan (when seen
from the front).)
Turn on breaker.
Operate unit.
Phenomena
1) Overcurrent-related problems oc-
cur immediately after compressor
startup.
Error code : 4250
Detail code : 101, 106, 107, 128
2) There is a voltage imbalance be-
tween the wires after the inverter
output voltage is stabilized.
Greater than the larger of the fol-
lowing values: imbalance of 5% or
5V
1) Fan motor megger failure
Failure when the megger is 1Mohm
or less.
2) Fan motor disconnection
Standard: The winding resistance
is approximately several ohm.
(It varies depending on the tem-
perature, or while the inner thermo
is operating, it will be
Connector contact failure
Board side (CNINV1 and CNINV2)
Fan motor side
Connector contact failure
1) Overcurrent error occurs. (4255,
4256 Detail code 101, 104)
2) Logic error occurs. (4255, 4256
Detail code 111)
3) Position detection at startup error
occurs. (5305,5306 Detail code
132)
- 151 -
Remedy
a. Check items [1] through [3]
for problems.
b. Check that high and low
pressures are balanced.
c. Check that no liquid refrig-
erant is present in the
compressor.
→Go to "d." when the
problem persists after
compressor startup was
repeated several times.
d. Check that there is a pres-
sure difference between
high and low pressures af-
ter compressor startup.
→Check the high pressure
with LED monitor for
changes.
Replace the compressor if
there is no pressure differ-
ence. (the compressor
may be locked.)
Replace the INV board if there
is a voltage imbalance.
→When the error occurred, liq-
uid refrigerant may have been
present in the compressor.
Replace the fan motor.
ohm)
Connect the connector.
Connect the connector.
Replace the FAN board.
Replace the FAN board.
Normal
*When done checking, recon-
nect all connectors as they
were.
GB