I have had my Z590 FTW for a few months and I finally got around to using it in a build. After carefully installing all of the components I could not get the system to POST.  The fans and pump on the CLC turn and the led indicator just starts up with "00" and stays like that. When I had the GPU installed the LEDs on it illuminated.  I then removed everything to see if there was an obvious error and nothing seemed out of order.  With the motherboard out of the case I re set the CPU and the CLC, after attaching the 8 pin CPU power and the 24 pin power I still get the same results when I turn on the power button. 
 
I read that this can happen if there is no CPU cooler detected so I tried plugging the CLC into different fan ports on the MB, one thing I noticed is that the pump header wouldn't power the CLC and I was wondering if that could be related to the issue. 
 
The PSU and CLC were removed form my Z370 build and both were working just fine.
 
Any advice would be appreciated.  

The CPU cooler needs to be plugged into the CPU header on the motherboard. This is regardless of whether you have an air cooler or AIO. 

Thanks for the replies,
 
I flipped the switch on the BIOS, both had the same result. 
 
As far at the fan headers go I tried the three at the top left (labeled 2 CPU fan, and Fan. , of the motherboard,  the one at the top right.  And the one labeled pump below the SATA ports. The "Pump" header is the only only one that will not power up the AIO. I'm wondering if there needs to be certain type of plug on that header.
 
I do have the MB out of the case and put on the foam packaging to eliminate any case related issues.
 
I think I will look around for another CPU cooler and see if that gets me anywhere.
 
Thanks again for the replies.
 
 
 
 
 

At this point I can't get to any settings, I even removed the RAM altogether to see if I could get the memory errors. 
 
I did find an ancient stock Intel cooler with a 4 pin plug and put that in the pump header, the fan did come on but still would get past the 00 on the LED code.

I thought about getting another cooler but I decided to wait to chat with tech support.  I'll post any resolutions here.

Ck the PSU to CPU power at MB
 
remove the coin cell battery ... does MB boot ?
 
CK with different Mouse & KB ... it happens

It should boot to BIOS without the CMOS battery

I did check for bent pins, there were none that I could see.

UPDATE I just received the replacement board and it worked perfectly, one thing I noticed was that the LED on the IO cover lit up when the PSU was plugged in, this never happened on the first board I had.
 
Thanks for the assistance.

Odd thing with my original board was that the diagnostic LED was going bad and the day I received my replacement board via RMA, it stopped booting. Replacement board is good so far.