Troubleshooting - Toshiba MD-VNK802HEXE Service Manual

9

Troubleshooting

9-1. Failure diagnosis
(1) Before diagnosing failure
(a) Model
All models of Modular Multi Type (SMMS-i)
All models of Air to Air Heat Exchanger with DX Coil Unit (MMD-VNK✽✽✽, MMD-VN✽✽✽)
(b) Necessary tools / measuring instruments
• Phillips-head driver, flat-head driver, spanner, pliers, nipper, thumbtack for reset switch, etc.
• Tester, thermometer, pressure gauge, etc.
(c) Check the following before diagnosing. (The following phenomena are not malfunctions.)
No. Symptom
The compressor does not
run.
1
The indoor fan does not run. • Is the indoor / outdoor temperature out of range?
2
The outdoor fan does not
3 run, or the air speed
changes.
The indoor fan does not stop
4
running.
The ON / OFF button on the
5 remote control does not
work.
(2) Procedure
If a malfunction has occurred, follow the procedure below:
Failure
Check the check code on the
interface board of the center unit
NOTE
If the malfunction has been caused by the power failure other than the following check items or micro controller
malfunction due to noises, the diagnosis may be wrong. If there is a noise source, shield the remote controller wires
and signal wires.
• During 3-minute delay (within 3 minutes after the compressor is turned
off)?
• Is the thermo off?
• During fan or timer operation?
• During initial communication of the system?
• In Bypass mode?
• During forced fan OFF control?
• During COOL low temperature operation control?
• During defrosting?
During overheat elimination control when heating is stopped?
During external remote control?
Error
"E28"
Check the check code on the
interface board of the target terminal
Other errors
50
Check
Check the locations
and components