Mitsubishi Electric City Multi CMH-WM250V-A, Service Handbook

Page: 237 / 436

[7-8 Error Code Definitions and Solutions: Codes [6000 - 6999] ]
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- chapter 7 BS_07_E
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7-8-16 Error Code [6608]
1. Error code definition
No response error
2. Error definition and error detection method

When no response command is returned although acknowledgement (ACK) is received after transmission, an error is detect-
ed.

When the data is transmitted 10 times in a row with 3 seconds interval, an error is detected on the transmission side.
The address/attribute appeared on the display on the remote controller indicates the controller where an error oc-
curred.
3. Cause
1) The transmission line work is performed while the power is on, the transmitted data will collide, and the wave shape will be
changed.
2) The transmission is sent and received repeatedly due to noise.
3) Decrease of transmission line voltage/signal by exceeding acceptable range of transmission wiring.
Farthest: 200m [656ft] or less
Remote controller wiring: 12m [39ft] or less
4) The transmission line voltage/signal is decreased due to erroneous sizing of transmission line.
Wire diameter: 1.25mm
2
[AWG16] or more
4. Check method and remedy
1) If an error occurs during commissioning, turn off the power supply to the outdoor units, indoor units, hydro units, and LOSS-
NAYs for 5 minutes or longer, and then turn them back on.
 When they return to normal operation, the cause of the error is the transmission line work performed with the power on.
 If an error occurs again, check the cause 2).
2) Check 3) and 4) above.
 If the cause is found, correct it.
 If no cause is found, check 3).
3) Check the transmission waveform, and check the transmission line for electrical noise. For details, refer to the following
page(s). [8-4 Checking Transmission Waveform and for Electrical Noise Interference]
Noise is the most possible cause of the error "6608".
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