(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 pipe 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)
*
If the thermistor temperature data is normal (not open/short), that data is loaded into the control as valid data.
1
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.
*
If one thermistor is set to open/short, the values for SHd/SC will be different from the list above.
2
[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°C
OCH771C
COOL
27
5
°C
5
°C
25
45
80
50
35
5
30
5
°C
COOL
HEAT
45°C
5°C
Ta
Tb
Tc
Td
5°C
50°C
5°C
45°C
Operation mode
HEAT
20.5
°C
°C
45
°C
50
°C
22
°C
°C
*
5
°C
°C
*
80
°C
°C
*
°C
5
°C
*
7
°C
°C
5
*
30
°C
°C
*
5
°C
68
Remarks
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1
1
1
1
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2
2