McQuay MDS 180B User Manual

78 Service Manual SM-MDS_(ii)
High/low pressure switch trip error
Error Code: Decorative Error code #6, H4, H6, L1, 34, 41 (For MC301), E7, H1, L1 (For MDOM PCB), ER52 to
ER53, ER56 (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
Measure discharge /
suction pressure.
Within spec?
YES
Is the coil sensor and
pressure sensor resistance
characteristics normal?
Refer Appendix 7.3 & 7.5
Replace sensor
YES
Replace PCB
NO
YES
NO
Check on power supply and wiring
connection. Replace outdoor fan
motor if necessary
Replace ball valve
Is the pressure
switch functioning?
YES
Replace Pressure switch
Is the EXV working
properly?
Replace EXV
YES
YES
Turn on the unit
Check for any leakage. Release or
charge the unit with refrigerant
according to specification
NO
NO
NO
NO
NO
Outdoor fan motor working?
Is the pressure port
on OD PCB abnormal?
Fix the port/replace PCB
YES
NO
Is the outdoor ball
valve open/close
normally?
6

McQuay MDS 180B Specifications

General

Brand	McQuay
Model	MDS 180B
Category	Compressor
Language	English