Need an electricians's assistance. DELL Fans.

[Princemercury]

This will probably be a simple question to answer for someone...

Some background information:

We have a slew of DELL servers and our company has decided to implement a large scale water cooling solution for our data centers. As many of you know DELL has 3, 4 and 5 pin fan connectors built on their serverboards/motherboards and when a fan is disconnected from one of them you receive the annoying

Alert! Fan failure.
Press F1 to Retry / Continue, F2 to Run setup util...

You can not disable fan check in the System Setup on a DELL machine. So what I'm looking for is what do I need to not "short", eg with a resistor or a capacitor, but connect between the +5v and GND pins to dissipate the 5v of energy and make the system "think" there's a fan there.

Thanks.

+ Something cost effective that we can replicate thousands of times... And we can't use the pins on board to power the individual pumps because the male molex(s) are soldered on and don't provide enough power input.

[SephYuyX]

Firstly, why in the hell are you going water cooling? Thats a horrible idea, and it will just cause more of a pain.

Secondly, im pretty sure all youd have to do is create a closed circuit, those fans are fairly low voltage, so you could probably just make a make shift connection to a diode using a similar volted/amped diode to create a close circuit.

An easier solution may be just to keep the fan circuitry in there. If you dont plan on keeping the fans, just rip them apart, and insulate it.

[Princemercury]

Firstly, why in the hell are you going water cooling? Thats a horrible idea, and it will just cause more of a pain.

Short answer: Energy costs are rising and after a long time of research it is cheaper to water cool than forced air cooling for our data centers and server farms, in the long run. Yes, as for the pain in the ass and feasibility factor we're only initiating testing at our HQ office, if it poses to be a problem, we will revert and cancel implementation. If not, we move forward with the project nationwide at our larger campuses.

Secondly, im pretty sure all youd have to do is create a closed circuit, those fans are fairly low voltage, so you could probably just make a make shift connection to a diode using a similar volted/amped diode to create a close circuit.

Yeah, problem is no matter how low the voltage simply closing it off with a jumper could potentially cause a short. There are 2 5v and 2 12v circuits that need to be 'terminated'. DELL will not offer us support on this issue nor will they offer a revised BIOS for us to bypass the fan check. As for the diode, we'll look further into that, thanks for the possible solution.

An easier solution may be just to keep the fan circuitry in there. If you dont plan on keeping the fans, just rip them apart, and insulate it.

Correct, fan circuitry stays but fans and existing heat sink assembly must go. Today over 80% of sound generated by a server farm are products of cooling and power fans, we're trying to decrease the impact of it as much as possible. We also contracted for macro redundant power supplies to power all our blades but in some PowerEdge's, especially the stand alone non-modular units, DELL includes fan checks in the power fan too. Removing them is the first step, we're trying to solve the issue with the System Safety check.

[SephYuyX]

What I meant about the fan circuitry was the parts inside the actual fan, not on the MB. Literally break apart the fan, take out the rotor so nothings spinning, and just leave it in there. If your water cooling requires to use the fan control, just splice it.

If your fans have a 5v and 12v, just use two diodes in a Y formation. So 5v wire to diode to common ground, and 12v wire to diode to same common ground.

Havent looked at server MBs in years, let alone Dells, odd the BIOS is forcing the use of 4pin molex, and not just 3pin ones.

[Princemercury]

Oh I gotcha, a bit sloppy but it works none the less...

Here's the problem we have now, the CPU fans send a pulse signal through the pin (diff on 3 4 and 5) and they register under the damn check too. We have an electrician on site today who will try to give us a solution.

Yeah the BIOS is forcing checks, even tho differently, on all the fan connectors which is pretty annoying. As far as diodes go I think that will solve our power fan issue if it doesn't short. I'll post up what we finally end up doing in case anyone is interested.