Question regarding the FAN used by WD My Cloud EX2



I have a WD My Cloud EX2 product. Using the diagnositic tool in the dashboard I noticed the Disks temperature is 57 C° and the FAN “RPM is to 0”!!! The temperature

The entire case is hot. I attached an image in ITALIAN language that show the situation. The temperature is NORMAL but in my opinion there is something strange.

Must the NAS reach a particular temperature to start the FAN?

Regards, Angelo

Improving the Fan function and sleep mode in EX2
WD, Will my FAN EVER start spinning? :((
FAN RPM is always 0 (My Cloud Mirror 4TB)
Very fast transfer speed (58.6 MB/s)
Cual es la Temperatura Normal de un disk de 4TB
External cooling of wdmcex2
New 2.10.302 Firmware and other stuff
Very Disappointed with the EX2

do you feel the fan working or is it really turned off???

my NAS ex4 have allways the fan working (normaly is on the mininum RPM with 800 - 900 rpm

i dont know how ex2 works because i dont have one to compare but 0 rpm seems abnormal


WDTony have one ex2 and its the same like your so … it seems to be by design :slight_smile:


Angelo, I see the same issue as you do with my EX2.  High temps, fan showing 0 RPM, not really feeling any flow out of the top of the case, but very warm just from hot air rising.  I wasn’t comfortable with this so I placed a 100mm USB powered fan on top of the case to draw air out.  Right about the time I did that the EX2 completed all it’s initial hard work with the thumbnails it makes for all the photos, so I’m not sure what temp inprovement I would have seen from adding the external fan. 

In any case, it doesn’t seem right, and for systems that constantly are under load, I question the longevity of the drives in that sustained heat.


I requested the replacement of the warranted product with a new one. I will keep you updated on new product.

Regards, Angelo


seems to me a too much common problem to be a single malfuncion…


I had the exact same problem.  My unit would give me a warning about “overheating” but my fan speed was always reported as zero.  I was not able to see the fan spinning during normal operations, but this does not mean it was not spinning when I was not looking.  So I ran the built-in diagnostic routine, no problems were reported and I could see the fan moving during the diagnostic routine.  In normal operations when I would get the overheating message, the fan speed was always reported as zero RPM.

It seems to me that the diagnostic routine correctly makes the fan spin so no fan problem is then reported, which gives a person a false sense of no fan problem.

Two weeks ago I returned my unit for a refund because of the overheating (zero fan RPM) problem and I also had an ongoing problem with the built-in Amazon S3.  I would like to purchase another EX2 because I think the EX2 is a great value, but at this point I’m concerned about the overheating problem and I see other people are having the exact same problem.

Certainly it could be a hardware issue, but I wonder if its a software (firmware) issue.  I have no evidence or information to say either way, but in my situation since the diagnostic routine correctly made the fan spin, it makes me think the issue is more software/firmware.


As I said in my previous post, I love the great value of the EX2 so I purchased another after I returned my first EX2 for a refund.  I am still not convinced my unit was having a hardware issue with the fan, and I still believe the issue is/was more likely software/firmware related.

I would like to continue to track this issue and will do the best I can to keep an eye on my system, but it’s not easy to be present when the above reported condition occurs.  So I wonder if anyone else has experienced this issue?


Had the same problem first day I used it. Called tech support and they told me to return it. I asked them for and advance replacment because I had already loaded my data on it. They sent one and I got it and have not seen that problem happen on it.


I have had my replacement EX2 for over a week and I continue to monitor the zero RPM fan discussion. So far I have never seen the fan running (zero RPMs are always reported in the diagnostic window), not that it’s a problem; I’m just saying I have never seen the system report more than zero RPMs for the fan.

From the UI command console I ran the built-in NAS to USB backup utility copying about 800GB of data from one of the NAS’ shares to the USB (USB3) My Passport Ultra connected drive.  The process took several hours (probably more than 4). For whatever reason, running a NAS to USB backup pegs the CPU at 100% for virtually the entire process and the EX2 really starts to heat up.

When the NAS is idle, both drives seem to hover around 38 - 40 degrees C, but while the NAS to USB backup was running, the CPU was pegged at 100% and both drives reported a temperature above 51 degrees C (about 124 degrees F). Even as the heat started to rise, the fan continued to report zero RPMs. To the touch, the drives seemed quite hot but maybe that is still within standard operating range. For reference, the ambient temperature of the room was 70 degrees F.

I have two questions:

Is it normal when running the built-in NAS to USB backup utility for the CPU to be pegged at 100%?

Could someone from WD tell us at what temperature the fan is programmed to start operating?


MrqDude - see this thread for Mirror posted just minutes ago ->

My Cloud Mirror Critical System temperature

Cubernut1, thank you for that link, you seem to be one of the few people who seems to be on top of things around here.  It’s too bad we can’t get any type of meaningful response from WD on these questions, but I have a feeling the EX2 product management has instructued WD staff not to comment on these boards.

I thought HW_Engineer’s post contained some interesting insight and his observation of the EX2 fan seeming to start after the EX2 is reporting an unhealthy “critical” condition is a similar experience I’ve had in the past.  I wish WD would lower the threshold starting temperature of the fan or at least give us the ability to set the threshold temperature to something lower than the current setting.


On my mirror (8TB), the fan comes on when the drives are 56-57C. You can test yours just by transferring GBs to it and cover the top vent holes until you drives raise above this temp. Check your log to see if you ever get messages like this:

2014 Sep 6 01:52:54
Set Fan Speed To "LEVEL 1".

Carefull not watch this and not let your mirror get to hot.


I meant to say, “Careful TO watch this closely and not let the drives of system get to hot.”


Well, as painful as it’s going to be (I’m in Dubai and the unit came from Amazon) but it looks like RMA is in order. As soon as the drives hit 45C I get errors accessing the data. It’s impossible to copy/move large files (leave alone working with them). Network error? Nope, nothing wrong with the network - I can view the very same file with no problems whatsoever. This is attempting to move the file back to my PC:


The small fan spins up at the start up and then never moves. This should have been fixed ages ago with the firmware updates. Now I have no warm fuzzy feelings about safety of any data in the unit.

Strange that, say, Synology’s DS412+ sports 2x 100mm fans in the back to keep the drives in reasonable temperatures and WD opted for a tiny fan which is not even running when it is needed…


It’s too bad WD does not lower the “fan start temperature” or better yet, allow allow us to change (lower) the temperature threshold for fan startup somethere in the firmware or at the very least a “config” file in the operating system.

What’s really a shame is that WD does not offer any comment and/or advice on this thread, which contains some good information from group of EX2 advocates who wish to improve the EX2.


so… just to be sure.

The fact the the speed is 0 rpm is normal since the fan start at some defined temperature.

So this is not  a problem or issue is just as configured by wd.



Looks that way - I took the cover off of my unit and it (the fan) definitely spins up at start up of the unit. Then stops and does not move at all. This proves that the fan is actualy working, just not set to run. I haven’t had the unit up to the temps which would start it up - it kinda dies for all intents and purposes above 50C (failed file transfers, alleged network connection issues etc.)

Taking into account that the drives rated to up to 70C max operating temperature setting the fan to start at 56-57C looks like a miscalculation of sorts…


Lynxair, I think you are 100% on target.

This is why I wish WD would chim in on this point and better yet, give us the ability, either in the UI or an INI file in the O/S, to asjust lower the fan start temperature.


I agree with MrqDude’s idea to have an user-driven fan control. Being a very recent owner of a QNAP NAS, I am starting to appreciate the finer attention to details in a QNAP’s firmware - like the flexibility over fan control. Something like what I get there (see pic below - or until a mod approves the pic you can see it here -> ) would be an excellent improvement over WD’s present fan control where we are left in the blind about fan control threshholds. Currently on EX2/EX4/Mirror, we just know current drive temp and fan RPM (QNAP provides those two live metrics as well but you can set your own thresholds for fan control, if you like).


Thank you Cybernut1, I too am a Qnap owner (TS-269) and have resisted making public comparisons between the EX2 UI and the Qnap, but it is becoming more and more frustrating to see no response from WD on this subject.

To the WD staff, you have some highly experienced & enthusiastic NAS users who are also EX2 owners and are posting in these forums. We are highlighting a few issues that will enhance the stability / usability of the EX2. Other NAS manufacturers do provide some interaction (limited and measured) with their respective forums, we would love to see you do the same as we all wish to see the EX2 become a great product.