(5) Operation data during emergency operation
During emergency operation, no communication is performed with the indoor unit, so the data items needed for operation
are set to the following values:
Operation data
Intake temperature (TH1)
Indoor pipe temperature (TH2)
Indoor 2-phase pipe temperature (TH5)
Set temperature
Outdoor liquid pipe temperature (TH3)
Outdoor discharge temperature (TH4)
Outdoor comp. surface temperature (TH33)
Outdoor 2-phase pipe temperature (TH6)
Outdoor ambient temperature (TH7)
Temperature difference code
(room temperature - set temperature) (∆Tj)
Discharge superheat (SHd)
Sub-cool (SC)
*1. If the thermistor temperature data is normal (not open/short), that data is loaded into the control as valid data.
When the unit enters emergency operation and TH values are mismatched, set the thermistors to open/short.
And the unit runs emergency operation with the values listed above.
*2. If one thermistor is set to open/short, the values for SHd/SC will be different from the list above.
[Example] When liquid temperature thermistor (TH3) has an open or short circuit.
Thermistor
TH3
TH6
Regard normal figure as effective data.
TH4/TH33
Regard normal figure as effective data.
TH5
TH2
Discharge superheat (SHd)
Cooling = TH4(or TH33)−TH6 = Tc−Ta
Heating = TH4(or TH33)−TH5 = Td−50
Degree of subcooling (SC)
Cooling = TH6−TH3 = Ta−45
Heating = TH5−TH2 = 50−45 = 5:
OCH737B
COOL
27:
5:
5:
25:
45:
80:
50:
35:
5
30:
5:
HEAT
COOL
5:
45:
Tb
Ta
Td
Tc
5:
50:
45:
5:
Operation mode
HEAT
20.5:
45:
50:
22:
*1
5:
*1
80:
*1
5:
*1
7:
5
*2
30:
*2
5:
57
Remarks
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