Mitsubishi Electric PURY-P72 Service Handbook page 313

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[ IX Troubleshooting ]
1) BC controller: Phenomena when LEV is connected wrongly (reverse connection of LEV1 and LEV3) to the board.
Cooling-only
Non-cooling
SH12 small, SC11 small
SC16 small, branch pipe
SC small
BC controller sound
2) Check method of fully open state or fully closed state of LEV
ŒCheck LEV opening (pulse) on the self-diagnosis LED (Outdoor control board SW1).
Full open: 2000 pulses
Fully closed: 110 pulses (In the case of heating-only mode, however, the pulse may become 110 or more.)
ŒWhen LEV is fully open, measure the temperature at the upstream and downstream pipes of LEV, and make sure that there
is no temperature difference.
ŒWhen LEV is fully closed, check that there is no refrigerant flowing sound.
3) Refer to the chart below to judge LEV opening controlled by the values of the differential pressure and of the superheat.
(BC controller LEV basic operation characteristic)
LEV1
G, GA, HA
type
LEV3
GB, HB
LEV3
type)
HWE09130
Cooling-main
Non-cooling and non-heating
SH12 small, SC11 small
SC16 large, but branch pipe
SC small
BC controller sound
PHM large
Malfunction
Operation
Part
mode
mode
Inclined to
Heating only
close
Heating-
main
Cooling-
Inclined to
main
open
Cooling-only
Cooling-
main
Inclined to
close
Heating only
Heating-
main
Cooling-only
Cooling-
main
Inclined to
open
Heating only
Heating-
main
Cooling-only
Inclined to
Cooling-
close
main
Cooling-only
Inclined to
Cooling-
open
main
Phenomena
Heating only
Indoor heating SC small
PHM large
Content
Difference between high
pressure (P1) and interme-
diate pressure (P3) is large.
Difference between high
pressure (P1) and interme-
diate pressure (P3) is
small.
SH12 is large.
Difference between high
pressure (P1) and interme-
diate pressure (P3) is
small.
SC16 and SH12 are small.
Difference between high
pressure (P1) and interme-
diate pressure (P3) is large.
SH22 is large.
SH22 is small.
- 304 -
Heating main
Non-cooling
Indoor heating SC small
PHM large
Standards of judgment on
unit stable operation
0.3 to 0.4MPa
[44 to 58psi]
SH12 < 20°C [36°F]
0.3 to 0.4MPa
[44 to 58psi]
SC16 > 3°C [5.4°F]
SH12 > 3°C [5.4°F]
0.3 to 0.4MPa
[44 to 58psi]
SH22 < 20°C [36°F]
SH22 > 3°C [5.4°F]
GB
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