Operation Data During Emergency Operation - Mitsubishi Electric PUHZ-HRP71VHA Service Manual

(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 pipe temperature (TH2)
Indoor 2-phase pipe temperature (TH5)
Set temperature
Pressure saturation temperature (T
Outdoor pipe temperature (TH3)
Outdoor discharge pipe temperature (TH4)
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.
When the unit enters emergency operation and TH values are mismatched, set the thermistors
to open/short. And the unit runs emegency operation with the values listed above.
*2: If one thermistor is set to open/short, the values for each will be different from the list above.
*3: Only for VHA2, YHA2
[Example] When pipe temperature thermistor (TH3) has an open or short circuit.
Thermistor
TH3
TH6
Regard normal figure as effective data.
TH4
Regard normal figure as effective data.
TH5
TH2
T (*3)
63HS
Regard normal figure as effective data.
OCH425F
)
63HS
COOL HEAT
5
45
Tb
Ta
Td
Tc
5 50
45
5
Tf
Te
Operation mode
COOL HEAT
27
20.5
5 45
5 50
25
22
50 50 (*1, *3)
45 5 (*1)
(*1)
80 80
50 (*1)
5
35 7 (*1)
5 5
30deg (*2)
30deg
5deg 5deg (*2)
<VHA, YHA>
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 - 45 = 5 deg.
<VHA2, YHA2>
Discharge superheat (SHd)
Cooling = TH4 - T = Tc - Te
63HS
Heating = TH4 - T = Td - Tf
63HS
Degree of subcooling (SC)
Cooling = T - TH3 = Te - 45
63HS
Heating = T - TH2 = Tf - 45
63HS
68
Remarks
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