Mitsubishi Electric MXZ-18NV Service Manual page 37

No. Item
<Protection details>
a) In COOL or DRY mode
• The 2 - way valve opens.
• The compressor operational frequency decreases at a rate of 10 Hz/minute.
b) In HEAT mode
• The 2 - way valve opens.
• The compressor operational frequency decreases at a rate of 10 Hz/minute.
• The outdoor fan runs at the Low speed.
<Condition to release the protection>
The protection is released when the high pressure switch turns OFF, that is, the discharge pipe
pressure falls to 2.4±0.15MPa (24.5 ± 1.5 kg/cm
(3) Low pressure protection by low pressure switch (only MXZ-32NV)
• The compressor ON/OFF, operational frequency, 2 - way valve, and LEV opening are
controlled by the low pressure switch to protect excessive low pressure.
<Condition to active the protection>
The protection starts when the low pressure switch turns ON, that is, the suction pipe pressure
falls to 0.05 ± 0.04MPa (0.5 ± 0.4 kg/cm
<Protect details>
• The 2 - way valve opens.
• The compressor operational frequency decreases at a rate of 10 Hz/minute.
• The LEV opens at a rate of 20 pulse/minute. When such a status has continued for five
minutes, the compressor will turn OFF and the error content will be displayed.
<Condition to release the protection>
The protection is released when the low pressure switch turns OFF, that is, the suction pipe
pressure falls to 0.15±0.04MPa (1.5 ± 0.4 kg/cm
(4) High pressure protection by high pressure switch (63H2 : MXZ-32NV )
• The compressor is turned OFF by the high pressure switch to prevent excessive high
pressure.
<Condition details>
The compressor stops operation.
<Condition to release the protection>
• The compressor is turned OFF once and turned ON again.
Details
2
) or below.
2
) or below.
2
).
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