Mitsubishi Electric PAC-IF051B-E Installation Manual page 39

. Main controller operation

Forced DHW

The forced DHW function is used to force the system to operate in DHW mode. In

normal operation the water in the DHW tank will be heated either to the set temper-

ature or for the maximum DHW time, whichever occurs first. However should there

be a high demand for hot water 'Forced DHW' function can be used to prevent the

system from routinely switching to space heating/cooling and continue to provide

DHW tank heating.

Forced DHW operation is activated by pressing button F1 and Back button in the

'Option Screen'. After DHW operation finishes, the system will automatically return

to normal operation. To cancel forced DHW operation hold down button F1 in the

'Option Screen'.

Heating/Cooling

The heating and cooling menus deal with space heating and cooling typically using

either a radiator or underfloor system depending on the installation.

From the main settings menu

1. Use F2 and F3 buttons to highlight heating/cooling icon then press CON-

FIRM.

2. The heating and cooling menu will be displayed.

3. To select the sub-menus press the function button below the icon required. E.g.

for mode change of Zone1 press F1

Heating/Cooling

1. Under this sub-menu the mode of heating or cooling is selected.

2. Choose between

• Heating flow temperature (

)

• Heating room temperature (

• Heating compensation curve (

• Cooling flow temperature (

)

Heating room temperature cannot be selected both in Zone1 and Zone2.

When Cooling flow temp. is selected in Zone1, Cooling flow temp is automati-

cally selected in Zone2. Zone1 and Zone2 are controlled at the same set

temperature. If using an underfloor system in Cooling mode, do not set the

flow temperature too low to avoid formation of condensation.

3. To choose between the different modes for heating and cooling, highlight the

mode preferred and press select.

If compensation curve mode was selected as the heating mode please read the fol-

lowing instructions.

Explanation of compensation curve

During late spring and summer usually the demand for space heating is reduced.

To prevent the heat pump from producing excessive flow temperatures for the pri-

mary circuit the compensation curve mode can be used to maximise efficiency and

reduce running costs.

The compensation curve is used to restrict the flow temperature of the primary

space heating circuit dependent on the outdoor ambient temperature. The FTC4

uses information from both an outdoor ambient temperature sensor and a tempera-

ture sensor on the primary circuit supply to ensure the heat pump is not producing

excessive flow temperatures if the weather conditions do not require it.

*This setting cannot be performed in cooling mode.

1. From the heating menu select edit using the F3 function button.

2. The compensation curve setting screen will be displayed.

3. In 2-zone heating operation, press F1 to switch between Zone1 and Zone2.

4. Press F2 to alter the Hi parameter (when flow temp is maximum and outdoor

ambient temp is minimum).

5. Press F3 to alter the Lo parameter (when flow temp is minimum and outdoor

ambient temp is maximum).

6. Press F4 to add an extra point (adjust).

Pressing F2-4 will cause the relevant edit screen to be displayed. Editing Lo and

Hi parameters is done in the same way; please see the following for more detailed

explanation of parameter editing.

In the parameter (Lo/Hi) edit screen the flow temperature and outdoor ambient

temperature for the compensation curve graph can be set and altered for the 2 ex-

tremes of Hi and Lo.

1. Press F1 and F2 to change the flow temperature (y-axis of compensation

curve).

2. Pressing F1 will raise the desired flow temperature for the set outdoor ambi-

ent temperature.

3. Pressing F2 will lower the desired flow temperature for the set outdoor ambi-

ent temperature.

4. Press F3 and F4 to change the outdoor ambient temperature (x-axis of com-

pensation curve).

5. Pressing F3 will lower the outdoor ambient temperature for the set flow tem-

perature.

6. Pressing F4 will raise the outdoor ambient temperature for the set flow tem-

perature.

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