Trouble
Check the check display
on the interface P.C. board
of the header unit.
[E28] error
Check the check display
on the interface P.C. board
of the corresponding follower unit.
Check position
or part in which
a trouble occurred.
Other error
8. TROUBLESHOOTING
8-1. Troubleshooting Summary
1. Before troubleshooting
1) Applied models
c
S-MMS Multi type models
Indoor unit
: MMX-APXXX,
Outdoor unit : MMY-MAPXXXXT8X, MMY-MAPXXXHT7X
d
Super Heat Recovery Multi type models
Indoor unit
: MMX-APXXX,
Outdoor unit : MMY-MAPXXXFT8X
e
Mini-S-MMS Multi type models
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.
1
2
3
4
5
6
Operation
Compressor does not operate.
Indoor fan does not work.
Outdoor fan does not rotate, or
fan speed changes.
Indoor fan does not stop.
Start/stop operation on remote
controller is unavailable.
——
Check items
• 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?
2. Troubleshooting procedure
When a trouble occurred, advance the check operation in the following procedure.
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.
FILE NO. SVM-17045
- 44 -
