Troubleshooting - Toshiba MMU-AP0094HP1-E Service Manual

8-1. Troubleshooting Summary
1. Before troubleshooting
1) Applied models
SMMS (i) Multi type models
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Indoor unit : MMX-APXXX,
Outdoor unit : MMY-MAPXXXXT8X, MMY-MAPXXXHT7X
Super Heat Recovery Multi type models
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Indoor unit : MMX-APXXX,
Outdoor unit : MMY-MAPXXXFT8X
Mini-SMMS Multi type models
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Indoor unit : MMX-APXXX,
Outdoor unit : MCY-MAPXXXHT, MCY-MAPXXXHT2X
2) Required tools / measuring devices
• Screwdrivers (Philips, Minus), spanner, radio pinchers, nipper, push pin for reset switch, etc.
• Tester, thermometer, pressure gauge, etc.
3) Confirmation before check (The following items are not troubles.)
No. Operation
1 Compressor does not operate.
2 Indoor fan does not work.
3 Outdoor fan does not rotate, or
fan speed changes.
4 Indoor fan does not stop.
5 Start/stop operation on remote
controller is unavailable.
6 ——
2. Troubleshooting procedure
When a trouble occurred, advance the check operation in the following procedure.
Check the check display
Trouble on the interface P.C. board
of the header unit.
NOTE
While a check operation is performed, a malfunction of the microprocessor may be caused due to condition of
the power supply or the external noise.
If there is any noise source, change wires of the remote controller and signal wires to shield wires.

8. TROUBLESHOOTING

• Is not delayed for 3 minutes? (3 minutes after compressor-OFF)
• Is not thermostat OFF?
• Is not the fan operating or timer?
• Is not the system initially communicating?
Heating operation cannot be performed under condition of outside
temperature 21°C or higher.
Cooling operation cannot be performed under condition of outside
temperature –5°C or lower.
• Is not the cold draft prevention being controlled in heating operation?
• Is not low cooling operation being controlled?
• Is not a defrost operation being performed?
• Is not after-heat elimination operation being controlled after heating
operation?
• Is not auxiliary unit or remote control being operated?
• Is connecting wire of indoor unit or remote controller correct?
[E28] error Check the check display
on the interface P.C. board
of the corresponding follower unit.
– 57 –
Check items
Other error
FILE NO. SVM-16041
Check position
or part in which
a trouble occurred.