Mitsubishi Electric AHU-KIT-SP Manual page 33

● Abnormal temperature sensor (return air/ heat exchanger) broken wire/ short-circuit detection
(a) Broken wire detection
When the return air temperature sensor detects -50℃ or lower or the heat exchanger temperature sensor detect -50℃ or lower for 5seconds continuously, the compressor stops.
After 3-minute delay, the compressor restarts but, if it is detected again within 60 minutes after the initial detection for 6 minutes continuously, stops again ( the return air temperature sensor: E7,
the heat exhanger temperature sensor: E6)
(b) Short-circuit detection
If the heat exchanger temperature sensor detects short-circuit for 5 seconds continuously within 2 minutes to 2 minutes 20 seconds after the compressor-ON during cooling operation,
the compressor stops (E6).
●Fan control during defrost control and oil return control
・During defrost control (defrosting control) and oil return control, it is necessary to stop the fan motor on the AHU side.
・However, if the fan motor cannot be stopped under the conditions of use of the air handling unit,
fan operation can be continued during defrosting and oil return only if the following conditions are met.
If the following conditions are not met, stop the AHU fan motor during defrosting and oil return signal output.
< Condition >
・Only when the difference in height between the outdoor unit and the AHU heat exchanger is 20[m] or less.
●Forced OFF control of compressor by return air temperature
If used beyond the range of use for air conditions, it will stop the compressor for protection.
・During cooling mode operation, the compressor-OFF if the AHU interface return-air temperature (detected with Thi-A)
is detected for 4 minutes continuously less to 12.0℃, or overs to 33.0℃.
<Cooling>
4 minutes
12℃ 13℃
・During heating mode operation, the compressor-OFF if the AHU interface return-air temperature (detected with Thi-A)
is detected for 4 minutes continuously less to 0.0℃, or overs to 30.0℃.
<Heating>
4 minutes
0℃ 1℃
Temperature drop
Temperature rise
4 minutes
compressor-ON
compressor-OFF
32℃ 33℃
Return air temperature:Thi-A
Temperature drop
Temperature rise
4 minutes
compressor-ON
compressor-OFF
29℃ 30℃
Return air temperature:Thi-A
MODEL NAME
Air Handling Unit Interface
MODEL TYPE
AHU-KIT-SP
ISSUE CLASSIFICATION
SPECIFICATION
MORIKAWA
DWG NO.
REV.MARK PAGE
PSZ000Z308
21.09.17
33/38