HP Z2 G4 SFF 901 Chassis Fan not detected (REAR)

[TeamWasabi]

Hi,

I have an HP Z2 G4 SFF workstation, no dedicated graphics card.

when I turn the unit on I get an error

FAN DETECTION ERROR

901 CHASSIS FAN NOT DETECTED (REAR)

I'm at lost on how to resolve this... the unit did not came with a rear fan only the CPU fan, just for test, I replace the CPU, clear CMOS/BIOS & still getting the same error

If I need to install a rear fan to get rid of this message , i might do it.. but can not find the PN for the REAR fan assy..

Any help is appreciated..

Roy

ps. found an old thread https://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/Rear-fan-and-fan-d...

but the part# for the rear fan noted is for a Z240 SFF not Z2 G4 SFF...

[SDH · Accepted solution]

Download this for your files. Search through it:

https://content.etilize.com/User-Manual/1059160490.pdf

HP Partsurfer is maddening sometimes:

Search for "HP Z2 Small Form Factor G4"... do not, I repeat, do not search for HP Z2G4 or HP Z2 G4 as you will come up empty.

From there you can look around and find this:

My guess is that you don't know where to look. Try starting at the back of the workstation and look for perforations, and look inside, and ignore the power supply perforations. No way there is not a rear fan unless someone snuck in and stole it.

[DGroves]

these systems (SFF) only came with a rear fan if the system came with the 85/90 watt ac adapter which powered the performance cpu's

so you either have the 85/90 watt adapter with a low power cpu, or you have the high power cpu/adapter

check what cpu is installed

https://www.cpuid.com/softwares/cpu-z.html

diverter (for low power systems)

https://pcxssolutions.com/hp-fan-diverter-rear-z2-g4-sff-l38202-001/

 the fan is a 60mm 4 pin PWM type, 834547-001 HP 60x25mm SPS-Fan Rear System for Z240 SFF will also fit z2 G4 SFF

if you  can't find the HP fan spacer, you can use 2/4 threaded bolts/ spacers and tape to make the fan sit half inch away from the case or just bolt the fan directly to the case

https://www.youtube.com/watch?v=jRcEWqzy2Nc

[TeamWasabi]

SDH,

Thank you for your quick reply...

I'll source the 834547-001... 

Though I like your theory of "someone snuck in & stole the fan".. my users are ' too clueless' to even open the panel, let alone mess with what's inside... good one !

What I dont get is, why of all of a sudden, I got the 901 error message that I never had before.. nothing changed, memory/HDD was intact.. only thing I can remember doing was blew the dust from the unit......😕

Thanks again !

[TeamWasabi]

DGroves,

Thank you for the reply too..

I dont follow the 85/90 W Ac Adpater, there is none..

see attached pic, the PSU (max 310W).. the pen shows where the plug the rear chassis fan...

as I said to my reply to SDH, I'll source the 834547-001 & go from there.. but still confused on what the h*** happen to have the mb caused a901 error..

[SDH]

I think DGroves deserves the solution kudos here, not me. His prior answer on this issue includes a link to the black plastic "diverter" that holds the 60 x 25 mm fan, and that link still works. Here is a 60 x 25 mm fan (EDIT: It actually is a 70 x 25 mm fan for the Z2 G4 SFF rear chassis fan if present) that probably would work fine:

https://www.ebay.com/itm/392575404159?hash=item5b6751487f:g:-5UAAOSwysFcIWXL

Be careful with small fans that have higher amperages... I saw some up to 3.3A which are whiner fans for servers. The one from Europe I found for 834547-001 is in the pic below (0.55A) but if you look at the fan plug end it does not look like the usual red-brown end we see in HP case fans so often... check your header on the motherboard. You'll have to go to the original address shown in the pic to shift the pic to the plug end: The DGroves YouTube HP video link shows the usual HP case fan plug end, by the way.

EDIT: THE INFORMATION THAT THIS 60X25 REAR FAN FROM A Z240 WILL FIT APPEARS TO BE IN ERROR. ALSO THIS FAN'S PLUG END SHOWN IN THE ONLINE AD BELOW DOES NOT APPEAR TO BE A STANDARD HP CASE FAN TYPE>>> NOTE LATER IN THIS THREAD THAT THE CORRECT HP FAN FOR A Z2 G4 SFF REAR CASE FAN (IF PRESENT) HAS A DIFFERENT FOXCONN PART NUMBER AND IS ACTUALLY 70x70x25mm IN SIZE... AND ALSO HAS A TYPICAL HP CASE FAN PLUG END WITH THE USUAL RED-BROWN PLASTIC COLOR HP OFTEN USES FOR THESE.

If you go to eBay and look up pva060g12n you'll see a fair number of those Foxconn fans... the ones with the red brown plastic plug end are easy to spot in there... from HP. Of interest sometimes HP fans will have their part number on the fan label and sometimes not. The little added alphanumerics  (-P16-AB in the pic above) are unique codes for lead length and fan plug type. Fans always blow towards their round label... face it out of the case.

I recently dug up a couple of my old posts for my "Ghetto Mods" that I always did to get case fans added to the older xw generation of workstations... go to this forum's search bar above and type in Ghetto and you'll see those for a while now. The easy access you show to the case perforations will help you, and the size/length of screws I used were for my HP ghetto 92 x 25 mm fans so they also would work for you perfectly. I got them from Ace Hardware and used stainless. Ferrous can be nice, however, because magnetic screwdrivers can hold them nicely. Add a 60 mm fan grill to the inside face of the fan if you don't get a HP black plastic mount cage.

In conclusion, it truly is a mystery that the motherboard would demand a fan now when it did not before. This raises a concern that it will still demand one after you feed it. I'm amazed that HP would not put a rear case fan in all of these... it is not that expensive a kit to use if they just did it for all!

[DGroves]

if you watch the HP link i provided you will hear the person refer the internal power supply as a "adapter"

also look carefully at the HP video and you will see the fan holder for the 95 watt system is different from the low power diverter shroud which appears to simply direct the hot air from the cpu out the back of the case although i suspect it could be adapted to mount a 60 or 50mm fan

the 95 watt part does not cover this, it simply provides a mounting solution/spacer for the 70x25mm fan,...... the spacer allows the fan to be a bit more efficient in moving air

https://www.youtube.com/watch?v=jRcEWqzy2Nc

HP Z2 G4 95W rear case Fan System  bracket: L13267-001   fan: L28631-001

https://www.ebay.com/itm/333854735018

here's a link to the HP  heatsink diverter,......... part number:  SPS:820942-001  which took a fair bit to track down

i'm still a bit confused as to why HP appears to use two different cooling solutions,....... diverter shroud only or rear fan  + mounting adapter for the z20/z240 systems it's not like HP to make a setup like this

BTW my "PCXS" link sells both type parts part for  28.00/15.00 and it appears to be in stock

Diverter only 28.00 fits on rear of heatsink and touches rear case does not appear to use a fan, although i suspect a 60/50mm fan could be made to fit

https://pcxssolutions.com/hp-fan-diverter-rear-z2-g4-sff-l38202-001/

cpu heatsink fan type diverter 15.00 (hp video shows this is what's used in 95 watt systems)

it appears to fit on the front of the heatsink where the cpu cooling fan is

https://pcxssolutions.com/fan-diverter-ws-sff-l38201-001/

[TeamWasabi]

SDH,

Thanks for that.. I ended up buying the 834547-001 from HP Parts directly, though it is currently on b/o, for about $70.00

Again appreciate the great response

[TeamWasabi]

DGroves,

YES, you are correct, maybe am old school, when someone says AC ADAPTER, in my brain, I automatically picture that to an external power source.. not internal.. maybe that just me...

But, I really do appreciate your input on this topic...

Thank you so much for your response...

[SDH]

Here is the fan I am now confident is for your rear case attachment... I checked the SFF motherboard and it has the same usual rear case fan header with matching red brown plastic holding the pins. Then searched eBay for Z2 G4 SFF fan and got some pics from England... one has a HP sticker showing exactly the L38200-001 spares part number from the HP Partsurfer screen capture I showed above. Note the pic below shows the newer black Foxconn fan label, and it has the HP assembly part number on it (L13267-001). That is a number that it might be listed under in eBay because that is easy for a seller to find and list and currently if you do that you'll find the whole kit. Tricks of the scrounger trade...

Now we know it truly is a 0.9A  Foxconn PIA070G12H fan with -P05-DB modifier. I now don't trust the source for the pic I had added of the Foxconn fan higher in this thread. Note the H in this new correct fan's label... that means it is a fan built to run at high speeds. HP then applies its motherboard PWM speed reduction to that H fan and it will slow down to exactly the speed they intended, with best longevity. They've used this method for years.

Also... the "70" in its name... that is a 70 x 25 mm fan, not a 60 x 25 mm one.

The motherboard does not know the amperage of the fan... this is the right one, but it will usually run slower than full high. The Noctua PWM fans already run slow and thus when you add the HP PWM braking they usually run too slow... they are great fans but not for this use. As long as you get the right size and that HP type fan plug end and rough correct amperage you'd be fine. I understand a purchase order rather than eBay (plus brand new) is what you IT guys need to use.