Midea Precision AC Technical Manual MCAC-PDSM-2013-01
94
Annex I: Alarm table
Alarm display
Result
Probable reason
Low pressure compressor 1
Switch off the compressor 1.
10s after the low pressure switch is
trigged.
Lose of airflow (Serious Alarm) UNIT OFF
Switch off the unit
10s after the airflow switch from close to
open.
Main fan overload(Serious Alarm) UNIT OFF Switch off the unit
Indoor fan motor protector acts.
EL heater1 overload
Switch off the E-heater 1
The overload protector of E-heat 1 acts.
EL heater2 overload
Switch off the E-heater 2
The overload protector of E-heat 1 acts.
Fire / Smoke detected(Serious Alarm) UNIT
OFF
Switch off the unit
Fire/smoke protector acts.
Power alarm
Switch off the unit
Phase
sequence protector is trigged.
High room temperature
It keeps 10s after difference between Ta
and Ts is higher than design value. The
unit will alarm.
Low room temperature
It keeps 10s after difference between Ta
and Ts is lower than design value. The unit
will alarm.
High room humidity
It keeps 10s after difference between Ha
and Hs is higher than design value. The
unit will alarm.
Low room humidity
It keeps 10s after difference between Ha
and Hs is lower than design value. The unit
will alarm.
Operating hour threshold reached for
compressor 1
Only remind, need to cancel alarm.
Operating hour threshold reached for mail
fan
Only remind, need to cancel alarm.
Room temperature probe faulty or
disconnected
Switch off E-heater and
compressor
a
ǃ
When Ta is lower than -30°C and
keeping 60s, alarms and switches off
all the E-heater. When Ta is lower
than 50°C, 999.9°C will be displayed.
b
ǃ
When Ta is higher than 80°C and
keeping 60s, alarm and switch off
compressor. When Ta is higher than
95°C, 999.9°C will be displayed.
Supply temperature probe faulty or
disconnected
a
ǃ
W
hen Ts is lower than -30°C and
keeps 60s, unit will alarm. When Ts is
lower than -50°C, -999.9°C will be
displayed.
b
ǃ
When the supply air temperature is
higher than 80°C and keeps 60s, unit
will alarm. When it is higher than
95°C, 999.9°C will be displayed.
Room humidity probe faulty or disconnected
Switch off humidifier and
compressor
a
ǃ
When Ha is lower than 5% and it
keeps 60s, unit will alarm and
switch off humidifier.
b
ǃ
When Ha is higher than 90% and
it keeps 60s, unit will alarm and
switch off compressor.
Condenser 1 pressure probe faulty or
disconnected
Switch off compressor
a. When discharge pressure
displayed is lower than -3.4bar
and it keeps 60s, the unit will
alarm.
b. When discharge pressure
displayed is higher than 37.4bar
and it keeps 60s, unit will alarm.
