Mitsubishi Electric PUY-A12NKA7, Service Manual

Page: 64 / 120

64
(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
Operation mode
Remarks
COOL HEAT
Intake temperature (TH1) 81°F [27
:
] 69°F [20.5
:
]
Indoor fluid pipe temperature (TH2) 41°F [5
:
] 113°F [45
:
]
Indoor 2-phase pipe temperature (TH5) 41°F [5
:
] 122°F [50
:
]
Set temperature
77°F [25
:
] 72°F [22
:
]
Outdoor liquid pipe temperature (TH3) 113°F [45
:
] 41°F [5
:
] (*1)
Outdoor 2-phase pipe temperature (TH6) 122°F [50
:
] 41°F [5
:
] (*1)
Outdoor air temperature (TH7) 95°F [35
:
] 45°F [7
:
] (*1)
Outdoor suction (TH32) 41°F [5
:
] 41°F [5
:
] (*2)
Temperature difference code
(intake temperature − set temperature) (∆Tj)
5 5
Discharge super heat (SHd) 54°F [30
:
] 54°F [30
:
] (*2)
Sub-cool (SC) 9°F [5
:
] 9°F [5
:
] (*2)
*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 COOL HEAT
TH3 113°F [45
:
] 41°F [5
:
]
TH6
Ta Tb
Regard normal figure as effective data.
TH4
Tc Td
Regard normal figure as effective data.
TH5 41°F [5
:
] 122°F [50
:
]
TH2 41°F [5
:
] 113°F [45
:
]
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
OCH636A