118
<Conditions to start defrosting>
The system starts defrosting when it satisfies both of the following conditions :
①
The defrost thermistor detects -3°C or below.
➁
Defrost interval (I. e. the accumulated compressor operation time) counted by the controller board has reached the
prescribed value.
<Details of defrosting>
①
The compressor stops for 32.5 seconds and the indoor fan turns OFF.
➁
The reversing value reverses and the compressor runs at the defrosting frequency.
③
After the defrosting termination conditions are satisfied, the compressor stops for 32.5 seconds and the reversing valve
reverses. This is the end of defrosting.
<Conditions to terminate defrosting>
The system terminates defrosting when it satisfies, either of the following conditions :
①
The defrost thermistor d10°C or above.
➁
Defrosting time has reached 10 minutes.
(1) High pressure protection in heating
• The operational frequency, 2 - way valve (only MXZ-32RV), and outdoor fan motor are controlled according to the
indoor coil temperature.
When it rises to nearly 50°C, the operational frequency will be fixed to the value at the moment and the outdoor fan
speed will change to low.
When it rises to nearly 53°C, the operational frequency will be reduced by 4 Hz from the current value and the 2 - way
valve will open.
(2) High pressure protection by high pressure switch (H.P.S : MXZ-18RV , 63H1 : MXZ-32RV)
• The operational frequency, 2 - way valve (only MXZ-32RV), and outdoor fan motor are controlled by the high pressure
switch to protect excessive high pressure.
<Condition to active the protection>
The high pressure protection starts when the high pressure switch turns ON, that is the discharge pipe pressure rises to
2.75 MPa (28 kg/cm
2
) or above.
<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
2
) or below.
(3) Low pressure protection by low pressure switch (only MXZ-32RV)
• 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
2
) or below.
<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
2
).
(4) High pressure protection by high pressure switch (63H2 : MXZ-32RV )
• 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.
+ 0.5
- 1.0
+ 0.05
- 0.1
11-10.7.Defrosting in heating
11-10.8.High and low pressure protection
