Mitsubishi Electric CITY MULTI PQRY-P200YMF-B Service Handbook page 125

(2) Communication/system
Checking
Meaning, detecting method
code
6600 Multiple address error
Transmission from units with the
same address is detected.
Note:
The address/attribute
shown on remote
controller indicates the
controller which has
detected error.
6602 Transmission processor hardware
error
Though transmission processor
intends to transmit "0", "1" is dis-
played on transmission line.
Note:
The address/attribute
shown on remote
controller indicates the
controller which has
detected error.
Cause
1) Two or more controllers of heat
source unit, indoor unit, remote con-
troller, BC controller, etc. have the
same address.
2) In the case that signal has changed
due to noise entered into the trans-
mission signal.
1) At the collision of mutual transmission data generated during the wiring work or polarity
change of the transmission line of indoor or heat source unit while turning the power
source on, the wave shape is changed and the error is detected.
2) 100V power source connection to indoor unit or BC controller.
3) Ground fault of transmission line.
4) Insertion of power supply connector (CN40) of plural heat source units at the grouping of
plural refrigerant systems.
5) Insertion of power supply connector (CN40) of plural heat source units in the connection
system with MELANS.
6) Faulty controller of unit in trouble.
7) Change of transmission data due to the noise in transmission.
8) Connection system with plural refrigerant systems or MELANS for which voltage is not
applied on the transmission line for central control.
–122–
Checking method & Countermeasure
At the genration of 6600 error, release the error by
remote controller (with stop key) and start again.
a) If the error occures again within 5 minutes.
→ Search for the unit which has the same address
with that of the source of the trouble.
When the same address is found, turn off
the power source of heat source unit, BC
controller, and indoor unit for 5 minutes or
more after modifying the address, and then
turn on it again.
b) When no trouble is generated even continuing
operation over 5 minutes.
→ The transmission wave shape/noise on the
transmission line should be investigated in ac-
cordance with <Investigation method of trans-
mission wave shape/noise>.