McQuay MDS 150B - Page 86

80 Service Manual SM-MDS_(ii)
System malfunction error
Error Code: Decorative Error code #8, E0, 10 (For MC301), E8 (For MDOM PCB), ER55 (For MDS-M PCB)
YES
Is the coil sensor and
pressure sensor correctly
connected?
NO
Ensure no obstacle around the unit
and conduct inspection on coil and
filter
Connect correctly and operate
again
Sufficient airflow?
YES
NO
Is the coil sensor and
pressure sensor resistance
characteristics normal?
Refer Appendix 7.3 & 7.5
NO
Replace sensor
YES
YES
NO
Replace outdoor fan motor
NO
Replace ball valve
Is the pressure
switch functioning?
YES
NO
Replace Pressure switch
Is the EXV working
properly?
NO
Replace EXV
YES
YES
Turn on the unit
6
Outdoor fan motor working?
Is the outdoor ball
valve open/close
normally?