8.1. Indoor fan speed adjustment
The IUC inside the indoor unit controls a variable speed indoor fan using a 0-10V signal from output
V1. Factory default settings for the output voltage provided on output V2 are:
• Off 0V
• Low 5V
• Medium 6.5V
• High 8V
It is possible to adjust these voltages. If the unit is controlled by a SAT-3 thermostat then placing the
SAT-3 in fan speed setup mode will allow adjustment via the keypad on the SAT-3 thermostat. For
more information on this refer to the SAT-3 installer manual.
If the unit is not controlled by a SAT-3 thermostat then by default the fan speed settings are
determined by DIP switch settings on the IUC. For more information refer to the manual for the IUC.
In installations where access to the indoor unit is restricted it could be more convenient to adjust the
indoor fan speed settings from the UC8 in the outdoor unit. If this is the case then turn on UC8 DIP
switch 5, remove power and then re-apply power to the unit. After that the fan speed settings can be
adjusted as follows:
To adjust the fan high speed setting:
Hold down UC8 pushbutton SW3 until the display shows the letter “H”, then release the
button. The UC8 will enter “fan high speed setup mode”. The display will show the current
high-speed voltage setting, e.g. “8.0” and the indoor fan will run accordingly.
Use the pushbutton to change the voltage from 3.0 to 10.0V in steps of 0.5V.
When the desired fan high speed has been set then wait 30 seconds, the controller will save
selected setting.
To adjust the fan low speed setting:
Hold down UC8 pushbutton SW3 until the display shows the letter “L”, then release the
button. The UC8 will enter “fan low speed setup mode”. The display will show the current low
speed voltage setting, e.g. “5.0” and the indoor fan will run accordingly.
Use the pushbutton to change the voltage from 1.0 to 8.0V in steps of 0.5V.
When the desired fan low speed has been set then wait 30 seconds, the controller will save
selected setting.
Notes:
1. It is allowed to select a low speed voltage equal to the high speed voltage. In effect the fan
then operates as a fixed-speed fan at the selected control voltage.
2. Fan medium speed voltage is always halfway between the low and high control voltages.
3. Fan off voltage is always 0V.
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