(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 fluid pipe temperature (TH2)
Indoor 2-phase pipe temperature (TH5)
Set temperature
Outdoor pipe temperature (TH3)
Outdoor 2-phase pipe temperature (TH6)
Outdoor air temperature (TH7)
Temperature difference code
(intake 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.
If the unit enters emergency operation because TH values have become mismatched, setting the thermistors
to open/short corrects the settings.
2: If one thermistor is set to open/short, the values for each will be different.
[Example] When pipe temperature thermistor (TH3) has an open or short circuit.
Thermistor
TH3
TH6
TH4
TH5
TH2
Discharge superheat (SHd)
Cooling = TH4 - TH6 = Tc - Ta
Heating = TH4 - TH5 = Td - (50
Degree of subcooling (SC)
Cooling = TH6 - TH3 = Ta - (45
Heating = TH5 - TH2 = 50
or
= 122°F - 113°F = 9degF
Operation mode
COOL
27 , 81°F
5 , 41°F
5 , 41°F
25 , 77°F
45 , 113°F
50 , 122°F
35 , 95°F
5
30degC,54degF
5degC, 9degF
COOL
45 , 113°F
Ta
Regard normal figure as effective data.
Tc
Regard normal figure as effective data.
5 , 41°F
5 , 41°F
or 122°F)
or 113°F)
- 45
= 5 degC.
HEAT
20.5 , 69°F
45 , 113°F
50 , 122°F
22 , 72°F
5 , 41°F
( 1)
5 , 41°F
( 1)
7 , 45°F
( 1)
5
( 1)
30degC,54degF
5degC, 9degF
( 2)
HEAT
5 , 41°F
Tb
Td
50 , 122°F
45 , 113°F
52
Remarks