Mitsubishi Electric ECOV-X37VA Manuel D'installation page 53

11-5-2. Preventing short-cycling operation
1) Checking if the operation is in short-cycling or not
Check the cycle of operation/stop time. If it is within 15 minutes, the operation is in short-cycling.
Eliminate the cause of the short-cycling.
The unit is equipped with a delay timer (at a maximum 200 seconds) to prevent frequent short-cycling operations.
2) Preventing short-cycling operation (frequent repeat of operation/stop)
As an essential measure to prevent short-cycling operation, the operation pattern needs to be set as shown in the figure.
• Short-cycling operation may cause a lack of lubricating oil
because of a large oil trip at the startup.
• A large amount of current flows to the built-in motor when
the unit starts, which may cause the motor to be overheat-
ed, resulting in burn-damage to the coil.
3) Major cause of short-cycling
Followings are possible major causes of short-cycling.
• Setting failure of low pressure control
For example, the low pressure differential is set to 0.2 MPa or below.
• Clogged strainer <suction>
• Leakage in the injection circuit or in solenoid valve <liquid> on the evaporator side caused by device fault or foreign sub-
stances.
• Refrigerant undercharge
• Condensing unit selection error (Unit capacity is too large.)
• Frosted evaporator
11-5-3. Troubleshooting
[1] How to check the error history
If the following code and value are shown on the digital display of the MAIN board, perform troubleshooting according to "Er-
ror codes and messages for troubleshooting" in the DATA BOOK.
• 4-digit code → Detailed code → 000H → Low pressure (Alternating blinking display)
• After the test run, check for leakage.
Operation
Min. 5
minutes
Min. 15 minutes
53
Time
Stop
Min. 5
minutes
WT09614X03_GB