Mitsubishi Electric PUHZ-P100VHA2 Service Manual page 58

Error Code Abnormal points and detection method
Communication error with
communication processor
Defective communication between unit
processor and transmission processor
Note) The address and attribute display
A6 at remote controller indicate the
(6606) controller that detected abnormality.
NO ACK signal
1. Transmitting side controller detects
abnormal if a message was transmitted
but there is no reply (ACK) that a
message was received. Transmitting
side detects abnormality every 30
seconds, 6 times continuously.
Note) The address and attribute displayed
at remote controller is indicate the
controller that did not reply (ACK).
A7
(6607)
2. If displayed address or attribute is
outdoor unit, indoor unit detects
abnormality when indoor unit transmitted
to outdoor unit and there was no reply
(ACK).
3. If displayed address or attribute is
indoor unit, remote controller detects
abnormality when remote controller
transmitted to indoor unit and there was
no reply (ACK).
OCH415F
Case
1 Data of transmission processor
or unit processor is not
transmitted normally because
of accidental trouble such as
noise or thunder surge.
2 Address forwarding from unit
processor is not transmitted
normally because of defective
transmission processor
hardware.
Common factor that has no
relation with abnormality source
1 The unit of former address
does not exist as address
switch has changed while the
unit was energized.
2 Extinction of transmission wire
voltage and signal is caused by
over-range transmission wire.
• Maximum distance......200m
• Remote controller line...(12m)
3 Extinction of transmission wire
voltage and signal is caused by
type-unmatched transmission
wire.
Type.....
With shield wire-
CVVS, CPEVS
With normal wire (no shield)-
VCTF, VCTFK, CVV
CVS, VVR, VVF, VCT
Diameter....1.25mm² or more
4 Extinction of transmission wire
voltage and signal is caused
by over-numbered units.
5 Accidental malfunction of
abnormality-detected controller
(noise, thunder surge)
6 Defective of abnormality-
generated controller
1 Contact failure of transmission
wire of outdoor unit or indoor unit
2 Disconnection of transmission
connector (CN2M) of outdoor unit
3 Defective transmitting receiving
circuit of outdoor unit or indoor
unit
1 During group operation with
indoor unit of multi- refrigerant
system, if remote controller
transmit to indoor unit while
outdoor unit power supply of
one refrigerant system is put off
or within two minutes of restart,
abnormality is detected.
2 Contact failure of transmission
wire of remote controller or
indoor unit
3 Disconnection of transmission
connector (CN2M) of indoor unit
4 Defective transmitting receiving
circuit of indoor unit or remote
controller
58
Judgment and action
Turn off the power supply of outdoor unit,
indoor unit and FRESH MASTER or LOSSNAY
at the same time for 2 minutes or more, and
turn the power on again. System returns
normally if abnormality was accidental
malfunction. If the same abnormality generates
again, abnormality-generated controller may be
defective.
Always try the followings when the error
"A7" occurs.
1 Turn off the power supply of outdoor
unit, indoor unit and FRESH MASTER or
LOSSNAY at the same time for 2 minutes
or more, and turn the power on again. If
malfunction was accidental, the unit returns
to normal.
2 Check address switch of abnormality-
generated address.
3 Check disconnection or looseness of
abnormality-generated or abnormality-
detected transmission wire (terminal block
and connector)
4 Check if tolerance range of transmission wire
is not exceeded.
5 Check if type of transmission wire is correct
or not.
If there were some troubles of 1-5 above,
repair the defective, then turn off the power
supply of outdoor unit and indoor unit and
FRESH MASTER or LOSSNAY at the same
time for 2 minutes or more, and turn the power
on again.
• If there was no trouble with 1-5 above in
single refrigerant system (one outdoor unit),
controller of displayed address or attribute is
defective.
• If there was no trouble with 1-5 above in
different refrigerant system (two or more
outdoor units), judge with 6.
6 If address of abnormality source is the
address that should not exist, there is the
unit that memorizes nonexistent address
information. Delete useless address
information with manual setting function of
remote controller.
Only the system FRESH MASTER or
LOSSNAY are connected to, or the system
that is equipped with group setting of
different refrigerant system.
If there was no trouble with 1-6 above, replace
the controller board of displayed address or
attribute.
If the unit does not return normally, multi-
controller board of outdoor unit may be
defective (repeater circuit).
Replace multi-controller board one by one to
check if the unit returns normally.
Continued to the next page.