Mitsubishi Electric PQRY-P200YEM-A Service Handbook page 107

Symptom
4 "88" appears on re- [Generates at registration and confirmation]
mote controller at 1) Erroneous address of unit to be coupled.
registration and
2) Disconnection of transmission line of unit to be
access remote
controller 3) Faulty circuit board of unit to be coupled.
4) Installation miss of transmission line.
[Confirmation of different refrigerant system controller]
5) Disconnection of power source of outdoor unit to be
6) Disconnection of centralized control transmission
7) Power supply connector (CN40) is not inserted into
8) More than 2 sets of power supply connector are
9) In the system connected with MELANS, power
10)Short circuit of centralized control transmission line.
Cause
coupled (No connection).
confirmed.
line (TB7) of outdoor unit.
centralized control transmission line in grouping
with different refrigerant system without using
MELANS.
inserted into the centralized control transmission line
of outdoor unit.
supply connector (CN40) is inserted into the
centralized control transmission line of outdoor unit.
a) Confirm the address of unit to be
coupled.
b) Check the connection of transmission
line.
c) Check the transmission terminal block
voltage of unit to be coupled.
i) Normal if voltage is DC17 ~ 30V
ii) Check the item d) in case other than i).
d) Confirm the power source of outdoor unit
to be coupled with the unit to be
confirmed.
e) Confirm that the centralized control
transmission line (TB7) of outdoor unit is
not disconnection.
f) Confirm the voltage of centralized control
transmission line.
i) Normal in case of 10V ~ 30V
ii) Check the items 7) ~ 10) left in case
–106–
Checking method & countermeasure
other than i).