Lennox LM012CI-100V232-1X Service Manual page 20

Service Manual
② Protection function
◆ Freeze protection
During operation, when controller detected that Ttube≤0℃ for a consecutive period of time, the system enters into freeze protection. In
that case, the compressor and the ODU fan stop operation, while the IDU operates at set fan speed. If freeze protection is released and
the compressor has been out of operation for 3 mins, the unit will resume its previous operation status.
◆ Overcurrent protection ( this protection function is not available for those models whose cooling capacity ≤12000Btu/h)
During operation process, if controller detected that system current exceeds the limit value for 3s consecutively (overcurrent), only the
fan operates. About 3 mins later, if overcurrent is released, the system will resume original operation.
If overcurrent protection occurs for 6 times consecutively, and resume operation time won't exceed 6min every time, overcurrent protec-
tion information will be displayed. After turning off the unit, display won't be displayed.
If turn on the unit again, the system will be restated up again. Overcurrent protection information will be eliminated.
Please refer to maintenance part for display information and disposal method for details.
◆ Locked protection to IDU fan motor
During operation of IDU fan motor, if controller detected that the rotation speed of IDU fan motor less than 300/min or stop rotation, the
motor operates abnormally. In order to prevent damage to motor, controller will protect automatically, the system stops operation and
blocked information of IDU fan motor will be displayed. After turning off the unit, display won't be displayed.
If turn on the unit again, the system will be restated up again. Blocked information of IDU fan motor will be eliminated. (For some models,
they can only be restated up after re-energized)
Please refer to maintenance part for display information and disposal method for details.
(3) Drying mode
① Operation condition and process for drying mode
◆ When Tamb. >Tset+2℃ , the system starts drying and cooling. In this case, the compressor and the ODU fan motor operate, and the
IDU fan motor operates at low speed.
◆ When Tset-2℃ ≤Tamb. ≤Tset+2℃ , the system will start drying. In this case, the IDU fan motor operates at low speed; the compressor
and the ODU fan motor operate for 6 minutes and stop for 4 minutes in cycle.
◆ When Tamb.<Tset-2℃ , the compressor and the ODU fan motor stop, while the IDU fan motor runs at low speed.
In drying mode, the 4-way valve is de-energized (4-way valve is not available for cooling only unit); Temperature setting range is
16~30℃ . Fan speed can't be adjusted.
② Protection function
◆ Freeze protection
During dying and cooling operation, when the controller detected that Ttube≤0℃ for a period of time consecutively, the system will enter
into freeze protection. In that case, the compressor and the ODU fan motor stops operation, while the IDU fan motor operates at low
speed. When freeze protection is release and the compressor has stopped for 3min, the system will resume original operation.
During drying operation, when the controller detected that Ttube≤0℃ for a period of time consecutively, the system enters into freeze
protection. In that case, the compressor, the ODU fan motor stops operation, while the IDU fan motor operates at low speed. When
freeze protection is release and the compressor has stopped for 4min, the system will resume original operation.
◆ Other protection is same as that under cooling mode.
Technical Information
Compressor
Outdoor fan motor
Indoor fan motor
T
amb.
T +2
preset
T 2
preset-
Compressor
Outdoor fan motor
Indoor fan motor
Freeze protection period
3 min
Set fan speed
6 min 6min.
4min.
4min.
Low speed
Cooling
Drying
Stop
17