Communication Error With Communication Processor; No Ack Signal; Transmitting Side Controller Detects - Mitsubishi Electric Mr.Slim PUHZ-RP35VHA3 Service Manual

Error Code Abnormal points and detection method
Communication error with communica-
tion processor
Defective communication between unit
processor and transmission processor
Note) The address and attribute display at
A6 remote controller indicate the con-
(6606) troller 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 mes-
sage was received. Transmitting side
detects abnormality every 30 seconds, 6
times continuously.
Note) The address and attribute displayed
at remote controller indicate the con-
troller that did not reply (ACK).
A7
(6607)
2. If displayed address or attribute is out-
door unit, indoor unit detects abnormali-
ty when indoor unit transmits signal 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
transmits signal to indoor unit and there
was no reply (ACK).
Case
1 Data of transmission proces-
sor 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 hard-
ware.
Common factor that has no rela-
tion 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 transmis-
sion wire.
Type ······
With shield wire-
CVVS, CPEVS
With normal wire (no shield)-
VCTF, VCTFK, CVV
CVS, VVR, VVF, VCT
Diameter····1.25mm 2 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-gen-
erated 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 receiv-
ing circuit of outdoor unit or
indoor unit
1 During group operation with
indoor unit of multi- refrigerant
system, if remote controller
transmits signal to indoor unit
while outdoor unit power sup-
ply of one refrigerant system is
turned off or within 2 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 receiv-
ing circuit of indoor unit or
remote controller
55
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 nor-
mally if abnormality was accidental malfunction.
If the same abnormality generates again,
abnormality-generated controller may be defec-
tive.
Always try the followings when the error
"A7" occurs.
1 Turn off the power supply of outdoor unit,
indoor unit and FRESH MASTER or LOSS-
NAY 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-gener-
ated address.
3 Check disconnection or looseness of abnor-
mality-generated or abnormality-detected
transmission wire (terminal block and con-
nector)
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 trouble of 1-5 above,
repair the defect, then turn off the power supply
of outdoor unit, indoor unit and FRESH MAS-
TER or LOSSNAY at the same time for 2 min-
utes or more, and turn the power on again.
• If there was no trouble with 1-5 above in sin-
gle refrigerant system (one outdoor unit), con-
troller of displayed address or attribute is
defective.
• If there was no trouble with 1-5 above in dif-
ferent 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 informa-
tion with manual setting function of remote
controller.
Only the system FRESH MASTER or LOSS-
NAY 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-con-
troller 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.