(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 liquid pipe temperature (TH3)
Outdoor 2-phase pipe temperature (TH6)
Outdoor air temperature (TH7)
Outdoor suction (TH33)
Temperature difference code
(intake temperature−set temperature) (∆Tj)
Discharge super heat (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 of SHd/SC will be different from the list above.
[Example] When liquid temperature thermistor (TH3) has an open or short circuit.
Thermistor
TH3
113°F [45:]
TH6
Regard normal figure as effective data.
TH4
Regard normal figure as effective data.
TH5
41°F [5:]
TH2
41°F [5:]
TH33
Regard normal figure as effective data.
Discharge superheat (SHd)
Cooling = TH4−TH6 = Tc−Ta
Heating = TH4−TH5 = Td−122°F [50:]
Degree of subcooling (SC)
Cooling = TH6−TH3 = Ta−113°F [45:]
Heating = TH5−TH2 = 50:−45: = 5˚C
or
= 122°F−113°F = 9˚F
OCH577A
COOL
HEAT
41°F [5:]
Ta
Tb
Tc
Td
122°F [50:]
113°F [45:]
Operation mode
COOL
81°F [27:]
69°F [20.5:]
41°F [5:]
113°F [45:]
41°F [5:]
122°F [50:]
77°F [25:]
72°F [22:]
113°F [45:]
41°F [5:]
122°F [50:]
41°F [5:]
95°F [35:]
45°F [7:]
41°F [5:]
41°F [5:]
5
54°F [30:]
54°F [30:]
9°F [5:]
69
Remarks
HEAT
(*1)
(*1)
(*1)
(*2)
5
(*2)
9°F [5:]
(*2)