MCQUAY DIGITAL SCROLL SYSTEM

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MCQUAY DIGITAL SCROLL SYSTEM
Troubleshooting
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SELF DIAGNOSIS
MDS Outdoor Unit
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SELF DIAGNOSIS
MDS Outdoor Unit

• Compressor Protection
• High low pressure switch / Sensor
• Overload protection input from compressor

• Monitoring Point (Temperature Sensor)
• Compressor Discharge
• Compressor Suction
• Ambient Temperature
• Coil Inlet
• Coil
• Coil Outlet
• Compressor

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SELF DIAGNOSIS
7 segment display on outdoor PCB
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SELF DIAGNOSIS
Indicator Code
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SELF DIAGNOSIS
ERROR Code
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SELF DIAGNOSIS
MDS Indoor Unit

• Temperature Sensor
• Coil Inlet
• Coil
• Coil Outlet
• Return air

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SELF DIAGNOSIS
ERROR Code
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SELF DIAGNOSIS
ERROR Code
Indication light twinkle related to malfunction
code
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TROUBLESHOOTING
Frequent Malfunction for Commissioning
Communication Error
Symptom For A series Outdoor, the 7 segment
display C- For B series Outdoor, the 7 segment
display EC78 For Wired Handset, the LCD panel
display FC For LED Display, the Heat LED will be
blinking
Potential Caused A The communication chip MAX485
of outdoor unit is damaged (Possibility is low.
The Communication is tested before ship
out) Solution To replace the MAX485 chip
Potential Caused B The communication wires A/B
get crossed each other or not connected (Most
common caused) Solution Check on all wiring.
Ensure proper tighten and the polarity is
consistent.
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TROUBLESHOOTING
Frequent Malfunction for Commissioning
Communication Error (cont)
Potential Caused C Shielding wire is connected
to ground terminal (not grounded). (Long wiring
and running the communication wire together with
power supply wire will cause this to
happen) Solution Ensure the shielding wire is
only grounded at the outdoor unit. Do not run the
communication wire with the power supply wire
together.
Potential Caused D Address of indoor are wrongly
set (Caution, the indoor address must be start at
0000 and follow. Do no jump the
number.) Solution Make sure the address start
from 0000, did not skip any address and no
repetition.
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TROUBLESHOOTING
Frequent Malfunction for Commissioning
Specific Indoor Communication Error
Symptom For A series Outdoor, the 7 segment
display CX (X Indoor Unit Number) For B series
Outdoor, the 7 segment display ECXX (XX Indoor
Unit Number) For Wired Handset, the LCD panel
display FC For LED Display, the Heat LED will be
blinking
Example For A series Outdoor, the 7 segment
display C3 (Indoor Unit Number 4 not
communicating) For B series Outdoor, the 7
segment display EC03 (Indoor Unit Number 4 not
communicating)
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TROUBLESHOOTING
Frequent Malfunction for Commissioning
Specific Indoor Communication Error (cont)
Potential Caused A Indoor Unit PCB has no power
supply. (Possible the power supply to the indoor
had been turned off) Solution Check the power
supply of the indoor power.
Potential Caused B Indoor Unit address
error. (Possible the indoor address is not set or
duplication) Solution Check the indoor model
address.
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TROUBLESHOOTING
Frequent Malfunction for Commissioning
Specific Indoor Communication Error (cont)
Potential Caused C Indoor Unit PCB
malfunction. (Possibility is low. PCB
communication is tested before ship
out.) Solution Replace with another PCB and
check the communication
Potential Caused D Wrong quantity of indoor
set. (Possible the quantity of indoor unit set in
the outdoor PCB is not tally with the actual
indoor quantity) Solution Check the quantity of
indoor unit setting at the outdoor PCB.
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TROUBLESHOOTING
If the followings malfunction occurred, please
follow the steps below to resolve
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Thank You