McQuay MDS030A, Service Manual

Page: 70 / 166

64 Service Manual SM-MDS_(ii)
EC
TH12 open/short circuit
(suction)

Outdoor suction temperature sensor TH12 broken or loose
73
EF
Emergency run

On the premise that part of the indoor unit communication malfunction and either one (or
both) of the following error occurs (unit will shut down):
1.
System sub heat <1ºC for 15 minutes
2. TH12 malfunctions
87
F0
Outdoor storage
malfunction

Outdoor PCB chip read faulty at the very beginning when power on

Outdoor PCB chip broken
82
F1
Indoor inlet coil sensor
malfunction

Indoor units T
in
sensor broken or loose
73
F2
Indoor midlet coil
sensor malfunction

Indoor units T
mid
sensor broken or loose
F3
Indoor outlet coil sensor
malfunction

Indoor units T
out
sensor broken or loose
F4
Indoor return air sensor
broken

Indoor units T
room
sensor broken or loose
F5
Indoor supply air sensor
broken

Indoor units T
room
sensor broken or loose
F6
Indoor and controller
communication
malfunction

Wired controller communication wire not connected or loose

Wired controller broken

Outdoor PCB broken
83
F7
Ambient temperature
exceed running range

Outdoor ambient temperature exceed running range
1.
cooling running range 0
– 43ºC
2. heating running range -15
– 16 ºC

Outdoor circulating air short
1.
Cause outdoor ambient temperature rising to exceed running range when cooling.
2. Cause outdoor ambient temperature falling to exceed running range when heating.
84
FA
Wired controller storage
broken

Data read faultily at the very beginning when power on

Chip broken
85
FB
Pump malfunction
(indoor drain pump)

Overflow switch broken

Pump broken
75
FC
Indoor and outdoor
communication
malfunction

Indoor and outdoor communication wire broken

Indoor and outdoor communication wire loose

Indoor and outdoor communication wire A and B reversed

Communication wire too long, should less than 1000m

Outdoor PCB not power on

Indoor and outdoor jump wire not correct, still on update status

Last indoor unit terminal resistance of communication wire not short-circuit

Indoor and outdoor PCB program not compatible

Indoor and outdoor PCB abnormal
76
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