PWM HUB Installation Question

[moondawg009]

Hi everyone I recently ordered some new components for replacing my old build which includes a new motherboard (MSI Gaming M5) and new case as well.

I am using the Phanteks Enthoo Pro which comes with the PWM HUB at the side of the case. It looks like both the front fan and back side fan are currently plugged into this out of box.

I have included a link to the case user manual here: http://www.phanteks.com/assets/manuals/PH-ES614P_Western.pdf

I am trying to make sense of the information on page 31 more specifically the *Important note* at the bottom of the page, I'm not familiar with the terminology.

It looks like it all may just be an optional feature in case I wanted to include more fans in the future and needed a power source, but I'm not sure if I should just plug the three pins for the fans directly into the motherboard like my previous one.

Thank you

 

[Darkbreeze]

That's just saying that it will use the PWM (Pulse width modulation) signal from a single fan header to control the speed of all fans connected to the hub. The hub should be connected to one of the motherboard fan hubs, any four pin header except the CPU_FAN header, which is where the CPU cooler or liquid cooling should be connected.

There are three four pin fan connectors besides the two CPU fan headers, and any of those three should work fine.

 

[Paperdoc]

It is intended that you use the Phateks PWM Hub as the connection point for ALL your case ventilation fans. The Hub requires connection to ONE mobo fan port, and all other SYS_FAN ports of a mobo are not used.

The instructions point out that the Hub MUST have a valid PWM signal. This is what its cable that ends in a female 4-pin fan connector is for. Phanteks points out that some mobo makers have provided as their SYS_FAN ports what amount to "fake" 4-pin ports. They have 4 pins, but they actually operate exactly as a 3-pin ports would in Voltage Control Mode and the fourth pin has NO PWM signal - it is useless. Thus as a precaution, Phateks advises that you plug this cable into the CPU_FAN port instead because almost all modern mobos use real 4-pin ports for this function, with a valid PWM signal on pin #4.

I disagree with Phanteks because ideally the case ventilation fans should be controlled by a SYS_FAN port which is guided by a temperature sensor on the mobo. (The CPU_FAN port is guided by a temperature sensor inside the CPU chip itself, and is not really ideal for governing case ventilation.) However, I agree with them that this opens up the possibility that the Hub might not operate correctly with some mobos. So I have a different suggestion, although a bit more complicated.

1. Plug your CPU cooling system into the CPU_FAN mobo port and let it control that cooler.
2. Plug the PWM Hub into one of the mobo's SYS_FAN 4-pin ports. Plug the other cable from the Hub into a SATA power output connector from the PSU to get power for all the Hub's fans. Plug all your case ventilation fans into ports on the Hub, but make SURE to connect one fan to the white Port #1.
3. Boot into BIOS Setup and go to where you configure SYS_FAN ports, particularly the one you are plugged into. Check what Mode the port is using. Sometimes you will have no choice, or it may talk only about something like a slope of PWM per degree. BUT if it gives you a choice of using PWM Mode or Voltage Control Mode, make sure you set to to PWM Mode. Save and Exit.
Now observe your case fans' actions carefully. What should happen normally is:
(a) at start up all fans should start at full speed for a few seconds, then all slow down.
(b) If you have the computer do a lot of work, you should hear the fans speed up at heavier loads and slow down when idling.
If that is what happens, everything is OK.

BUT if all your case fans only keep running at full speed all the time, then the Hub is not getting a PWM signal to use. This will force you to shut down and go back to Phateks' way: move the Hub's 4-pin fan connector to the mobo CPU_FAN port. Move the case fan on the white Port #1 of the Hub to another port. Then plug your CPU cooling system into that Port #1 of the Hub. This will put all fans - CPU and case vent - under control of the CPU cooling system, but it will at least be automatically adjusted according to computer workload.

Now, about the last note on manual page 31. This all has to do with fan speed readouts. Interestingly, cooling and speed control functions do NOT need this speed signal - it is only for information and for failure monitoring. All fans generate a speed pulse signal (2 pulses per revolution) and send it back to the mobo on Pin #3 of the fan port. The mobo counts those pulses so you can see its speed, and it also uses that signal to warn of fan failure if NO pulses are being fed back. Now, most mobo fan ports can provide enough power for 2 fans, but not more, so people use Y-splitters to connect 2 fans to one port. BUT if the splitter merely connects all three fan wires from each fan to the port, the the mobo counting circuit gets TWO slightly different pulse strings overlapping and gets VERY confused with bad readings. So, any decent Y-splitter only connects to the mobo ONE of its fan's speed signals, and the other fan's speed simply is never measured. Extend this to the case of the PWM Hub which can have up to six fans on its ports. The Hub is wired so that ONLY the speed signal of the fan plugged into its white Port #1 is sent to the mobo - all others are ignored.

Further of this two-on-one concept, the HUB's ports also can be used with Y-splitters to connect two fans to EACH of its ports. It comes with a couple of these (in case you have more than 6 fans), and you can buy more. However, Phanteks advises that you should NOT use a Y-splitter and connect two fans to that one special white Port#1.

 

[Darkbreeze]

Your suggestion that connecting two fans to each PWM hub header is ok is wrong, or at least, is somewhat dubious. While motherboard fan headers are capable enough of supplying power to two, but not more, fans, it's very highly doubtful that connecting more than six fans to a hub intended for use with only six, is a good idea and further it doesn't specifically recommend doing this in the manual so I would avoid doing so. It may be rated for 30w, which is below what six fans would be likely to draw, but if there were a problem with a fan that caused it to over draw it's normal maximum you might end up with a problem.

Personally, unless you have all 3 pin case fans, which you may or may not since some of them came with the case, I'd simply use the motherboard fan headers. It's more efficient and offers better control over each individual fan.

Much also depends on if you plan to use other fans, how many and whether they are three or four pin PWM fans too. I don't remember if the included fans with the Enthoo Pro are three pin, but if they are, then you may have to use the hub because your four pin motherboard fan headers might not support three pin voltage regulation. They might, some support both voltage and PWM controls, but many only support PWM OR voltage control, but not both.

 

[moondawg009]

Thank you for the replies, I don't really care to much about controlling the case fans I just want them to be running (even at 100% all the time I don't mind) and I wasn't sure if I needed to use this hub or not, so if I understand correctly my fans use 3 pins but the mobo sockets require 4 so I will need to keep he 3 pin fan cords in the fan hub and connect it to the motherboard for power.

A video I watched said to use the 12v cable if the motherboard is in compatible but I'm not sure, I'm not sure what the third paragraph is saying within the manual.

 

[Paperdoc]

The website for the Hub here:

http://www.phanteks.com/PH-PWHUB.html

specifically says it can support up to 11 fans totaling max 30W, and comes with two Y-splitters included to get you started. As it happens, for this particular thread this is no issue - OP intends only to use the three 3-pin fans included in the case. And yes, since these case fans are 3-pin, likely they will need to be plugged into the Hub because many (but not all) mobo SYS_FAN headers do not offer the option of Voltage Control Mode.

Let me explain a bit what the manual says on p. 31 regarding Hub installation.To power many fans this hub needs a 12VDC supply stronger than what comes out of a mobo SYS_FAN port. So one of the Hub's two cables terminates in a male SATA power connector and must be plugged into a matching female SATA power output connector directly from the PSU. If you fail to do this the Hub's only power source is the connection to the mobo port, and that can only power up to two fans. This has nothing to do with "compatible".

The manual also suggests that, IF the mobo SYS_FAN port really is operating in Voltage Control Mode and NOT providing a PWM signal, that varying voltage on port Pin #2 will cause malfunctioning of the Hub if it is also plugged into the proper 12 VDC supply from the PSU. So if you were to follow my suggestions in my prior post and find that the Hub cannot control fan speed because of lack of PWM signal, then you REALLY need to revert to the original Phanteks instructions and connect the Hub's fan cable to the mobo CPU_Fan port, and then arrange to power the CPU cooling system from Hub Port #1.

 

[Darkbreeze]

They are stating that if your four pin headers are voltage controlled, then do not use the SATA power cable to power the PWM hub. In your case, it seems the four pin fans are NOT PWM, except for the CPU headers, so what I'd probably do then is connect the CPU to the main CPU fan header and connect your hub to the optional CPU fan header, so that it gets it's proper PWM signal. OR, I'd connect your three pin fans to the four pin headers on the motherboard, since they are voltage controlled anyhow and should work normally from the profiles within the bios.

The temperature-based control scheme is limited to four-pin PWM fans attached to the CPU headers. The three system fan headers can drive both three- and four-pin fans—but only in DC (or voltage control) mode.

As to the power connection, that would eliminate the problem since you would not be using the hub. If you still choose to use the hub, then you would connect to the optional CPU fan header and connect power to the motherboard SATA power header as normal. If you connect to one of the system fan headers, which apparently are NOT PWM despite being four pin, you would not connect ANY power to the unit.

 

[moondawg009]

Thanks for the replies

Can any damage be done by connecting the 3 pin fan headers into the 4 pin motherboard sockets, because that sounds like the easiest thing for me to do.

I just want the two case fans to work without me breaking anything.

 

[Paperdoc]

Looking closely at the manual for your mobo on page 40, it appears darkbreeze is correct. The manual seems to say that all 3 SYS_FAN ports are actually operating as 3-pin ports in Voltage Control Mode only, even though they have an unused 4th pin. Thus you cannot get a PWM signal from any of those ports, and your only source of that signal is from either of the two CPU_FAN ports. Since you have two, you could use CPU_FAN1 for your CPU cooler, and CPU_FAN2 for the plug from the Hub, as darkbreeze said. Or, as darkbreeze also said, since you have three 3-pin fans and three mobo SYS_FAN ports that operate in Voltage Control Mode, simply plug the case fans into those mobo SYS_FAN ports and ignore the Hub altogether, leaving it completely disconnected.

The information in the manual makes experimenting unnecessary, and darkbreeze has the right plan.

 

[Darkbreeze]

No. It cannot, because they are meant for use with them on that board, apparently, according to the review data I've seen. I have not contacted MSI to ask them directly, so going off the reviews I read, they are meant for use with three or four pin voltage controlled fans, not with PWM fans, except for the CPU and CPU OPT headers. They should be fine in either case. Just make sure to line up the key/clips on the fan connectors with the corresponding alignment keys on the header. They should install over the three pins that are aligned with the key, not the fourth pin that's kind of off on it's own at the end of each motherboard header. You'll see what I mean when you go to install them. Just make sure they are using the three pins closest to the little lock tab on the header.

Like shown here, except your fans will have no fourth wire, which is yellow in this picture, so you'll use only the pins on the header that are centered to the lock tab, as shown.

 

[moondawg009]

Thank you both for clearing this up

 

[Darkbreeze]

Anytime moondawg.

 

[Paperdoc]

Let me suggest darkbreeze's contributions be marked for Best Solution.