CONTROL SYSTEM
11-3
SM FSF048 1-A.0 GB
11.8.3
Low Pressure Protection of Compressor by low pressure switch
•
Comp is on,
After the compressor has run for 2 minutes, the unit will begin to detect the signal of low pressure
switch, If it is detected within 60 seconds continuously that the low-pressure switch is cut off, the unit
will stop, 3 min later, if the protection is gotten over, the unit will resume operation automatically. Or
else, the fault (E3)will display and the unit can not resume operation automatically. it can resume by
pressing ON/OFF.
•
Comp is off
if it’s detected that the low pressure switch is cut off for 30s continuously, the unit will stop running.
Meanwhile, E3 will be displayed and the unit can’t resume running automatically. Only after restarting
up the unit and the low pressure switch is resumed, the unit can resume running.
11.8.4
Compressor over Heating Protection
After the compressor is started up, if it
’
s detected that the discharge temperature is too high for 30s
successively, the unit will stop running, When compressor has stopped for 3mins and discharge
temperature resumes to normal range CTT<90
℃
, the unit will resume running.
If above protection is occurred for twice successively, the complete unit can
’
t resume running and E4
will be displayed. When restarting up the unit and CTT<90
℃
, the unit will run at setting mode.
If turning on the unit to turn to heating mode or switching to heating mode from other modes, discharge
protection will be shielded for 1min when compressor is started up for the first time.
11.8.5
Compressor over Current Protection
After compressor is started up, if it’s detected that the current is exceeds I0 (I0=25A) for 3s
successively, the unit will stop running After compressor has stopped for 3mins, the unit will resume
original running status. If protection times exceeds 6 times, indicator will blink and display E5 and the
unit can’t resume original running status.
The unit can only resume running after restarting up the unit.
11.8.6
Outdoor Coil Deicing Protection
This protection is for Heat Pump Only
This protection is carried out by the cooling cycle (reverse cycle). The defrosting time or outdoor heat
exchanger temperature must be more than its setting values when finishing the deicing protection.
In the deicing protection, IFAN is forced OFF.
Deicing Starting Conditions
The starting conditions must be made with the outdoor air temperature (OAT) and outdoor coil
temperature (OCT). Under the conditions that the system is in heating operation for certain period
(Accumulated time)
Deicing process
H1 will be displayed during deicing. If there’s auxiliary heating, auxiliary heating will be stopped and
then compressor, indoor fan and outdoor fan will stop running after 1min delayed. 3mins later, the
four-way valve will be OFF. After four-way valve is OFF for 30s, compressor will be started up.After
deicing is finished, compressor will stop running, while the four-way valve will be ON. 30s later,
compressor and outdoor fan will be restarted up. Indoor fan is running at anti cold air status.
The max Deicing Time is 12 minutes.
11.8.7
Overheating protection in heating mode
In heating mode, when it’s detected that the evaporator tube temperature (ICT) is too high, outdoor
fan will stop running; when evaporator tube temperature resumes to normal range, outdoor fan will
be started up.
