Troubleshooting - Toshiba R410A Service Manual

9. TROUBLESHOOTING

9-1. Troubleshooting Summary
1. Before troubleshooting
1) Applied models
Super Heat Recovery Multi type models
(Indoor unit: MMX-APXXX, Outdoor unit: MMY-MAPXXXFT8)
2) Required tools / measuring devices
• Screwdrivers (Philips, Flat), spanner, longnose pliers, nipper, push pin for reset switch, etc.
• Digital multimeter, 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.
Start/stop operation on remote
5
controller is unavailable.
6 None
2. Troubleshooting procedure
When a fault has occurred, follow the procedure detailed below.
Trouble
NOTE) A malfunction of the microprocessor may be caused by power supply inconsistencies and external
noise. If there are any noise sources, move remote controller and signal wires away from the noise
sources or shield them.
• Is it delayed for 3 minutes? (3 minutes after compressor-OFF)
• Is thermostat OFF?
• Is the fan operating or timer?
• Is the system initially communicating?
Heating operation cannot be performed under the condition that the outside
temperature is 21°C or higher.
Cooling operation cannot be performed under the condition that the outside
temperature is –5°C or lower.
• Is cold draft prevention control operating at heating mode?
• Is it in low ambient cooling control?
• Is a defrost operation being performed?
• Is the fan operating to remove residual heat after heating operation?
• Is an auxiliary unit or remote controller being operated?
• Are the wire connections on the indoor units and remote controllers correct?
Check the check display
on the interface P.C. board
of the header unit.
Check items
Check position or part in
which trouble occurred.
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