Noctua NA-FC1 | User manual
“No stop” mode can be used in order to avoid motherboard fan errors that can occur below certain speed
levels or if the fan stops. To exit “no stop” mode, press the “no stop” mode push button again, so
that the green “no stop” mode status LED goes off.
Please note that many PWM fans have a minimum speed higher than 300rpm and as the function of
“no stop” mode is to not let fans go below 300rpm, it is only useful for fans which are generally able to
go below this speed. For example, a fan with 500rpm minimum speed will act the same with “no stop”
mode on and off.
Additional notes
PWM duty cycle and fan speed
Response to PWM input can vary from fan to fan and is not always linear, so for example some 2000rpm
fans may run at 1000rpm at 50% PWM duty cycle while others may run at 1200rpm. The NA-FC1 can
only set a specific duty cycle, not a specific fan speed. If you would like to set a specific fan speed, please
either use hardware monitoring software provided by the motherboard manufacturer or 3
rd
-party tools
like SpeedFan in order to check actual fan speeds during setup.
Minimum speeds and behaviour below 20% duty cycle
Note that some PWM fans will stop at duty cycles below 20% while others will keep running at the same
speed as they have at 20%. Also, the minimum speed achieved at 20% varies from fan to fan. As this is
determined by the fan’s motor and internal electronics, the NA-FC1 cannot make fans go slower or stop,
which are designed not to go below their 20% speed and/or have a high minimum speed setting. Please
refer to the fan specifications for the minimum PWM speed. If you want to prevent the fan from stopping,
please use the “no stop” mode.
Changing fans
When changing fans, please briefly disconnect the NA-FC1 from the power source first in order to make
sure that the cache is cleared and the new fan can be tracked correctly.
Lags when switching into “no stop” mode at low speeds
Please note that it may take up to 30 seconds until the fan is brought up to 300rpm when switching into
“no stop” mode at low speed settings.
40%
50%
30%
80%
60%
90%
70%
100%
0%
10%
20%
200
400
800
1200
1400
Fan speed (RPM)
PWM duty cycle signal
600
1000
original speed curve
(motherboard control only)
with NA-FC1 at 50% setting
with NA-FC1 at 50% setting
and “no stop” mode active
“No stop” mode
Regardless of whether the NA-FC1 works as a manual controller or adjusts an incoming PWM duty
cycle signal from the motherboard, turning the speed control dial to a very low setting (or using
low-speed fans) may result in very low fan speed or the fan stopping altogether. If you would like to
prevent the fan from stopping, press the “no stop” mode push button in order to activate “no
stop” mode. In “no stop” mode (indicated by the green “no stop” mode status LED being on),
the NA-FC1 will not allow the fan to fall below a minimum fan speed of 300rpm, regardless of how
low the speed control dial setting or incoming PWM duty cycle signal is:
Modes of use
If the NA-FC1 receives no PWM signal on the input side (from the motherboard), it will act as a manual
speed controller. The NA-FC1 will then generate a PWM signal between 0 and 100% PWM duty cycle
depending on the setting of the speed control dial . Turn the speed control dial clockwise to increase
speed and anticlockwise to reduce speed. The orange speed setting status LED will change in bright-
ness according to the speed setting.
Note that the NA-FC1 can be used in manual mode when powered both from motherboard fan headers
or from other power sources. It just depends on whether there is an input PWM signal or not, so simply
deactivate automatic fan control in the BIOS of your motherboard if you would like to use the NA-FC1
in manual mode.
a) Manual control
b) Adjusting automatic motherboard fan control
Turn the speed control dial clockwise to increase speed and anticlockwise to reduce speed. The orange
speed setting status LED will change in brightness according to the speed setting.
40%
50%
30%
80%
60%
90%
70%
100%
0%
10%
20%
500
1000
1500
2000
2500
Fan speed (RPM)
PWM duty cycle signal
original speed curve
(motherboard control only)
with NA-FC1 at 80% setting
with NA-FC1 at 50% setting
If the NA-FC1 receives an input PWM signal, it will adjust the incoming signal between 100% and
0%, depending on the setting of the speed control dial . For example, if the dial is set to 50%
and the motherboard provides a 100% PWM duty cycle signal, the NA-FC1 will reduce the signal
by 50%, thus giving an output PWM duty cycle of 50%. If the motherboard provides 80% and the
NA-FC1 is set to 50%, it will put out 40% etc. This way, the NA-FC1 will work in tandem with the
motherboard’s automatic fan control, allowing you to lower the original control curve in order to
achieve lower fan speeds and noise levels:
Connect the NA-EC1 input cable to the input connector and to the motherboard fan header or
other power sources. Then connect the fan to the output connector . If you want to control multiple
fans, first connect the NA-SC1 splitter cable to the output connector and the fans to the NA-SC1.
NA-AC4 input cable with power supply adaptor
Plug the S-ATA connector of the NA-AC4 to one of the S-ATA connectors of your power supply.
Plug the female 4-pin connector of the NA-AC4 to the motherboard fan header and the male 4-pin
connector to the NA-FC1’s input connector . Then connect the fan to the output connector .
If you want to control multiple fans, first connect the NA-SC1 splitter cable to the output
connector and the fans to the NA-SC1.
NA-EC1 input cable
Caution: Please bear in mind that common motherboard fan headers usually only support up to 9.6
or 12W (check your motherboard manual for detailed information). Exceeding this rating may per-
manently damage your motherboard and Noctua cannot be held responsible for any such damage.
Please always use the supplied NA-AC4 adaptor (see setup option
A
) if the combined power draw of
the connected fan(s) exceeds the max. power rating of the motherboard fan header.
