Mitsubishi Electric Mr.SLIM PUZ-A42NHA5-BS Service Manual page 53

(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 fl uid pipe temperature (TH2)
Indoor 2-phase pipe temperature (TH5)
Set temperature
Outdoor fl uid pipe temperature (TH3)
Outdoor 2-phase pipe temperature (TH6)
Outdoor air temperature (TH7)
Temperature difference code
(intake temperature - set temperature) (∆Tj)
Discharge super heat (SHd)
Sub-cool (SC)
w1: 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.
w2: 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 45:, 113°F
TH6
Regard normal fi gure as effective data.
TH32
Regard normal fi gure as effective data.
TH5
TH2
Discharge superheat (SHd)
Cooling = TH32 - TH6 = Tc - Ta
Heating = TH32 - TH5 = Td - (50: or 122°F)
Degree of subcooling (SC)
Cooling = TH6 - TH3 = Ta - (45: or 113°F)
Heating = TH5 - TH2 = 50: - 45: = 5 ˚C.
or
= 122°F - 113°F = 9˚F
OCH512
COOL HEAT
5:, 41°F
Ta Tb
Tc Td
5:, 41°F 50:, 122°F
5:, 41°F 45:, 113°F
Operation mode
COOL
27:, 81°F 20.5:, 69°F
5:, 41°F 45:, 113°F
5:, 41°F 50:, 122°F
25:, 77°F 22:, 72°F
45:, 113°F 5:, 41°F
50:, 122°F 5:, 41°F
35:, 95°F 7:, 45°F
5
30˚C, 54˚F 30˚C, 54˚F
5˚C, 9˚F
53
Remarks
HEAT
(w1)
(w1)
(w1)
5
(w2)
5˚C, 9˚F (w2)