Error Code For Phase Protector - McQuay MDS Series Service Manual

7.16 Error Code for Phase Protector

MDS unit is equipped with Scroll Compressor which can only rotate in one direction. For this reason, a protective
device (phase protector) is fitted to prevent incorrect wiring of the electrical phases. When the three phases are
not connected correctly, the phase protector operates, and the unit will not start. This device is located in the
control box of the outdoor unit.
The following table shows the LED indicator light for phase protector under normal and fault conditions.
Description
(Red)
Normal Operation
Reverse Phase BLINK
T Phase Missing BLINK
S Phase Missing BLINK
R Phase Missing BLINK
Remark: All error can only recover through manually reset.
Service Manual SM-MDS_(ii)
LED
PW P_R P_S
(Yellow) (Yellow)
ON OFF OFF
BLINK BLINK
OFF OFF
OFF BLINK
BLINK OFF
P_T
(Yellow)
OFF -
BLINK
BLINK Switch off the unit.
OFF Check the 3 phase wiring.
OFF
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