Symptom: Unit Operation Problems - Daikin VRV IV+ Service Manual

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2.4.20

Symptom: Unit operation problems

Symptom
Unit(s) do not operate
Operation sometimes stops
Operation stops and then restarts
after 3 minutes.
Unit operates but does not cool or
does not heat
RYYQ+RYMQ+RXYQ8~20U7Y1B
VRV IV+ Heat Pump
ESIE18-14 – 2019.07
Possible failure
Unit(s) do not operate
All indoor units show icon
blinking continuously
Indoor unit(s) show icon
blinking temporarily when ON
button is pressed
Indoor units show fan-only mode
Power failure
Outdoor unit performing 'retry'
operation
Piping or wiring mismatch
Abnormal refrigerant amount
Incorrect thermistor values
Incorrect expansion valve
operation
Cross piping/wiring among
different outdoor unit systems
Root cause
Missing or abnormal power supply
(reverse phase, missing phase,
abnormal voltage...) to the outdoor
unit
Indoor unit(s) do not receive power
supply
Mismatch of combination of
outdoor unit and indoor unit
Out of operation range
No Cool/Heat master is set
The unit(s) are either under
Centralized Control and prohibited
to operate or under Forced OFF
operation by T1/T2 input
Transmission initialization not
completed
A power failure consecutively more
than 2 cycles may stop the air
conditioner operation
Retry mode triggered by an error
Tranmission or piping problem
Outdoor unit may be overcharged
or lacking refrigerant
Thermistors not in their location,
miswiring or faulty thermistor
Expansion valve not operating
correctly
Indoor unit transmission line and
piping is not connected to the
same outdoor unit system
2 Troubleshooting
Repair
Check Power Supply. See
"4.1 Electrical circuit" on page 130
Check power supply to the indoor
unit(s), check if HAP Led blinks,
check fuse(s) on indoor unit board.
Also check BPMKs in case indoor
unit is of RA type.
Check error codes. Check
compatibility
Check operation range on
databook
Select Cool/Heat Master by
pressing Operating Mode button
on the desired unit. The symbol
will fade-away for Cool/Heat
Master and will be fixed (not
blinking) for the remaining indoor
units
Release prohibitions from central
controller or check T1/T2 contact
status or check indoor unit field
setting for forced off
See "To check F1-F2
transmission" on page 131.
Perform transmission re-
initialization
Check transmission wiring
Check indoor unit PCBs
Check outdoor unit main PCB, see
"3.9 Main PCB" on page 106
Restore power supply. See
"4.1 Electrical circuit" on page 130
Check field setting 1-23, 1-24, 1-25
for latest retry content. See
"6.9 Field settings" on page 188.
Refer to error code found for
further troubleshooting.
Correct piping, wiring
Check refrigerant amount. See
"4.2 Refrigerant circuit" on
page 133
Check thermistors, see
"3.17 Thermistors" on page 128
Check expansion valves. See
"3.5 Expansion valve" on page 89
Correct piping, wiring
Service manual
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