Asus Z170-Deluxe BIOS issue with fanless CPU cooler

[Ubtree]

I am building a PC with passive CPU and graphics coolers, based on an Asus 170-deluxe motherboard, but I have hit an issue with the BIOS: unless a CPU fan is installed, the BIOS refuses to boot the PC.

I have tried a work around, by connecting a fan to the CPU fan header, with the intention of switching it off - either in a basic BIOS or by using Q-Fan Control. However, I am unable to reduce the Fan Minimum Duty Cycle below 60%, and setting the CPU Fan Speed Lower Limit to "Ignore" does not help.

Any suggestions would be greatly appreciated.

[Abula]

There was an option on the Asus motherboards on the past, i don't remember the name, where you overwrite this issue of no fan on startup, but maybe newer bios have this removed.

The other option is just install a very low rpm fan, and connect it to the CPU header, Asus motherboard have the option to switch the CPU_FAN header from PWM to Voltage Controlled (in the Q_FAN, in the past was just to switch it from AUTO to ADVANCED).

Btw i though the new Z170 asus mobos had a FanXpert2 style of fan control on the BIOS, maybe run the tuning to see if it can go lower then the 60% you are referring (could be the fan though, not all fans go that low).

[Vicotnik]

It's not hard to build a rpm signal generator. Google gave me this hardforum thread.

But usually there's a BIOS option to ignore fan fail check.

[quest_for_silence]

But usually there's a BIOS option to ignore fan fail check.

It should be there (the "Wait for F1" check, I guess):

[Ubtree]

The other option is just install a very low rpm fan, and connect it to the CPU header, Asus motherboard have the option to switch the CPU_FAN header from PWM to Voltage Controlled (in the Q_FAN, in the past was just to switch it from AUTO to ADVANCED).

Btw i though the new Z170 asus mobos had a FanXpert2 style of fan control on the BIOS, maybe run the tuning to see if it can go lower then the 60% you are referring (could be the fan though, not all fans go that low).

It's not hard to build a rpm signal generator. Google gave me this hardforum thread.

But usually there's a BIOS option to ignore fan fail check.

Thank you for this inventive suggestion. It is a clever solution, but thankfully there is in fact a BIOS solution.

It should be there (the "Wait for F1" check, I guess):

Thank you for the pointer. You're absolutely right. I have disabled "Wait for F1 if Error", and now the PC boots. I can't believe that I missed it myself!!

Many thanks for all your help.