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MCQUAY DIGITAL SCROLL SYSTEM. Troubleshooting. SELF DIAGNOSIS. MDS Outdoor Unit. SELF DIAGNOSIS. MDS Outdoor Unit. Compressor Protection High & low pressure switch / Sensor Overload protection input from compressor. Monitoring Point (Temperature Sensor) Compressor Discharge
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MCQUAY DIGITAL SCROLL SYSTEM Troubleshooting
SELF DIAGNOSIS MDS Outdoor Unit
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
SELF DIAGNOSIS 7 segment display on outdoor PCB
7 Segment Display on outdoor PCB SELF DIAGNOSIS Indicator Code
LED of outdoor PCB SELF DIAGNOSIS ERROR Code
SELF DIAGNOSIS MDS Indoor Unit • Temperature Sensor • Coil Inlet • Coil • Coil Outlet • Return air
LCD Indicator of controller SELF DIAGNOSIS ERROR Code
LED Indicator of Receiver SELF DIAGNOSIS ERROR Code Indication light twinkle related to malfunction code :
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.
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.
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)
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.
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.
TROUBLESHOOTING If the followings malfunction occurred, please follow the steps below to resolve :