Mitsubishi Electric PUZ-HA30NHA5 Service Manual page 54

(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 liquid temperature (TH2)
Indoor 2-phase pipe temperature (TH5)
Set temperature
Outdoor liquid temperature (TH3)
Outdoor 2-phase pipe temperature (TH6)
Outdoor ambient 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−(122°F [50:])
Degree of subcooling (SC)
Cooling = TH6−TH3 = Ta−(113°F[45:])
Heating = TH5−TH2 = 122°F−113°F = 9°F
OCH607
COOL
81°F [27:]
41°F [5:]
41°F [5:]
77°F [25:]
113°F [45:]
122°F [50:]
95°F [35:]
54°F [30:]
9°F [5:]
COOL
113°F [45:]
Ta
Regard normal figure as effective data.
Tc
Regard normal figure as effective data.
41°F [5:]
41°F [5:]
[50:−45: = 5:]
Operation mode
HEAT
69°F [20.5:]
113°F [45:]
122°F [50:]
72°F [22:]
41°F [5:]
41°F [5:]
45°F [7:]
5
5
54°F [30:]
9°F [5:]
HEAT
41°F [5:]
Tb
Td
122°F [50:]
122°F [50:]
54
Remarks
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