3. Explanation of operation

1)Before the deice is started, compressor frequency is set to the specified value for T0-timer.

2)After deice is started, the 4-way valve, OD Fan and ID fan are OFF.

3)After 4-way valve is OFF for 30 s, compressor frequency is set to the specified value.

4)Before deice is ended, if the outdoor heat exchanger temperature exceeds a°C, set compressor frequency and expansion valve to the specified values.

5)When outdoor heat exchanger temperature exceeds b°C, or 10.5 minutes has passed since the 4-way valve is OFF, operation at timer T5 will be started.

6)After the above 5) operation, if the specified time has passed, the deice operation ending signal will be produced. The comp. Hz is set to the specified value and at the same time outdoor fan motor ON signal is produced.

7)After T6 the deice ending signal is produced, 4-way valve is set to ON, indoor fan is ON, Compressor frequency is FREE, and return to normal heating operation.

4.Deice operation judgement condition

When any of below a, b, c, d condition is satisfied, deice signal is produced.

a.Continuously, outdoor heat exchanger temperature < 3°C for 120 minutes and outdoor heat exchanger temperature < -5°C for 3 minutes and outdoor air temperature > -1°C and Comp. is ON.

b.Continuously, outdoor heat exchanger temperature < 3°C for 80 minutes and outdoor heat exchanger temperature < - 6°C for 3 minutes and outdoor air temperature > -1°C and Comp. is ON.

c.Continuously, outdoor heat exchanger temperature < 3°C for 40 minutes and outdoor heat exchanger temperature < - 7°C and outdoor air temperature -3°C for 3 minutes and Comp. is ON.

d.Continuously, outdoor heat exchanger temperature < 3°C for 40 minutes and outdoor heat exchanger temperature < - 8°C for 3 minutes and outdoor air temperature < -3°C and Comp. is ON.

However, the first deice will start only after minimum of 60 minutes in operation.

(2nd deice and onward shall follow above conditions)

B. Auto clean deice

1.Purpose

To improve heating start-up operation by detecting the residual ice on OD heat exchanger and perform deice operation automatically before operation is started by ON Timer.

2.Control Content:

1). Auto deice is performed 15 min. before standby operation (pre-deice operation in 15 min.).

2). When below deice conditions are fulfilled, auto clean deice operation will start.

3). After auto clean deice is completed, standby operation is performed as per load.

4). When deice conditions are not fulfilled, auto clean deice will not happen and will continue with standby operation.

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