Fedders R407C service manual Heat Mode Cycle

For example, if the temperature set point is 20°C when cool mode is entered at a room temperature of 21°C, the controller will start the cool mode cycle to cool the room.

The cycle still continues when the room temperature later lowers to 20°C. It finally stops when the room temperature lowers further to 19°C.

If the room temperature subsequently rises to 20°C again, the cool mode cycle will still not start. The cool mode cycle will only start when the room temperature rises further to 21°C.

In heat mode (applicable on Heat Pump Unit only), the heat mode cycle starts and stops according to the following rules:

Room temperature	< Set pt-1°C	= Set pt-1°C	= Set pt.	= Set pt+1°C	> Set pt+1°C
Heat Mode Cycle	Start	Start	*	Stop	Stop

*Maintain current state

For example, if the temperature set point is 20°C when heat mode is entered at a room temperature of 19°C, the heat mode cycle will start to raise the room temperature.

The cycle still continues when the room temperature later rises to 20°C, and eventually stops when the room temperature raises further to 21°C.

If the room temperature subsequently falls to 20°C again, the cycle will still not start. The heat mode cycle will only start when the room temperature descents further to 19°C.

5.Indoor Coil Protection Against Icing in Cool Mode

After switching on the compressor for 10 minutes in cool mode, the electronic air-con controller will detect the indoor coil temperature. If indoor coil temperature <6°C, the indoor fan will operate in accordance with the following table:

ID Coil Temp. Tr	Tr ≤ 4 °C	4°C<Tr<°6C	Tr≥6°C
ID Fan	High	*	Set

*Maintain current State

Indoor coil de-icing will be executed if indoor coil temperature is found to be less than 2ºC for 2 minutes. De-icing operation will stop if the indoor coil temperature reaches 10ºC or higher for 2 minutes. If not, it will be end de-icing operation after 10 minutes. While the indoor coil is being de-iced, the green LED on the LED board will blink at approximately 95 times per minute.

To de-ice the indoor coil, the air-con controller discontinue cooling it by turning off the compressor and outdoor fan. At the mean time, the indoor fan is left running at its set speed to speed up the ice-melting process via convection.

Normal cool mode operation will be maintained at its current state for the initial 3 minutes of de-icing operation. After this, the compressor and outdoor fan will be switched off.

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