McQuay 5MDS, Руководство по обслуживанию

Страница: 66 / 84

MCQUAY Service Guide Book Diagnosis
65
Rooftop Panel
Alarm Shown On The Rooftop Panel
• Whenever panel received a new alarm, an alarm message will pop up on the LCD. It shows type of alarm,
alarm occurred time and date. Backlight blinking (if Backlight is not OFF) and alarms buzzer produces
beeping sound (if it’s set ON). The buzzer will beep for 10 minutes after that stop for 5 minutes (with the
Backlight still blinking), this process keep looping until the alarm is dissolved or a key press is detected.
• Backlight will stop blinking via key press. Press UP or DOWN key to scroll the alarms display if more than
one alarms occurred. Press ESC to exit to the summary pages.
• If one of the alarms has been dissolved, pop up message will update its display (would not show the
dissolved alarm anymore). If all the alarms have been dissolved, it will exit to the summary pages
automatically.
• If the existing alarm has not been dissolved and another new alarm is occurred, the pop up message will
update to the latest alarm.
• A sign [A] will be shown and blink in Summary Pages as long as the alarm has not been dissolved. If user
needs to view current existing alarms, press “ALARM” key in the summary pages or go to ALARM MENU in
MAIN MENU.
• The panel can display up to 20 new alarms at once (which are not dissolve yet).
• All the incoming new alarms record will be store in ALARM MENU – Show Alarms.
• The alarm histories are viewable ONLY when all the new alarm already dissolved.
• If the contact type alarm is set to manual reset, the alarm can only be dissolved by off and on BACK
rooftop unit.
Error Message Possible causes Action
1. MB & economizer
communication fail
Communication wires not
connected Connect correctly and operate again.
External noise / interference Avoid from noise source / add ferrite core.
Main PCB / Economizer PCB
faulty Replace main PCB / economizer PCB.
2. Memory Error EEPROM data corrupted Replace main PCB and operate again.
3. Economizer Error Refer to the economizer board
error code table. Refer to the economizer board error code
table.
4. ESD contact open Normally close ESD contact
become open ESD contact shorted with wired. If fail,
replace main board and operate again.
5. Compressor 1 / 2
overload
Insufficient airflow / Air short
circuit Ensure no obstacle around the unit.
Heat exchanger dirty Ensure no dirt or dust on filter and coil.
Refrigerant overcharge /
undercharge Recharging with correct amount of
refrigerant.
Condenser fan motor faulty Replace fan motor.
EXV or EXV PCB defective Replace EXV or EXV PCB.
Compressor malfunction Replace compressor.
Main PCB faulty Replace main PCB.
6. Compressor 1 / 2 low
pressure trip
Refrigerant undercharge Top up with correct amount of refrigerant.
Pressure switch faulty Replace pressure switch.
Main PCB faulty Replace main PCB.
7. Compressor 1 / 2 high
pressure trip
Insufficient airflow / Air short
circuit Ensure no obstacle around the unit.
Heat exchanger dirty Ensure no dirt or dust on filter and coil.
Condenser fan motor faulty Replace fan motor.
Refrigerant overcharge Recharging with correct amount of
refrigerant.
EXV or EXV PCB faulty Replace EXV or EXV PCB.
High Pressure switch faulty Replace pressure switch.
Main PCB faulty Replace main PCB.
8. Compressor 1 / 2
discharge overheat
Discharge sensor malfunction Replace new discharge sensor.
Insufficient airflow / Air short
circuit Ensure no obstacle around the unit.
Heat exchanger dirty Ensure no dirt or dust on filter and coil.