Liebert GXT3 UPS Fan Question

JDUBS · « **on:** 22 Apr 2011, 02:49 am »

Guys, has anyone changed the fans in Liebert GXT3? I get a "fan fault" error when I changed the ones in my GXT3-2000 / 120. Not sure how to get around that.

Thanks,
Jim

jtwrace · « **Reply #1 on:** 22 Apr 2011, 02:54 am »

I haven't but...was it a direct replacement? Same voltage?

JDUBS · « **Reply #2 on:** 22 Apr 2011, 02:58 am »

Yes, same voltage, same size:

http://www.frozencpu.com/products/8398/fan-514/Noiseblocker_NB-Multiframe_M8-S2_80mm_x_25mm_Ultra_Silent_Fan_-_1700_RPM_-_14_dBA.html?tl=g33c165s356&id=6NRBIBnB

I have a GXT2-1500 and the fan swap was no problem. Its weird that this one is presenting a problem. The fans power on fine but there is a continuous beep and a red fault light on the front of the unit.

-Jim

JDUBS · « **Reply #3 on:** 23 Apr 2011, 04:39 am »

So, I was thinking...how does the UPS know if a fan is present? The new fans power up and spin just fine. I replaced the two wire fans with different two wire fans. I wonder if the UPS looks for a specific resistive load across the two terminals? I don't know how else it could tell WHAT fan is present (i.e., the new fans present a different load than the old fans). Is that how computers recognize if a fan is present when one is connected?

-Jim

jtwrace · « **Reply #4 on:** 23 Apr 2011, 11:26 am »

I can't answer the above. Sorry.

Do they come on at all? If so, is the rotation correct?

JDUBS · « **Reply #5 on:** 23 Apr 2011, 06:21 pm »

Yes, the fans spin perfectly fine...no issues with that, but there is no UPS functionality when there is a fault present.

I know a decent bit about computers but am only speculating in regards to how they detect the presence of fans...and why my UPS is doing what its doing.

-Jim

jtwrace · « **Reply #6 on:** 23 Apr 2011, 07:00 pm »

very odd. I'm sure you checked any and all fuses or resets including internal and any factory resets.

Bob in St. Louis · « **Reply #7 on:** 23 Apr 2011, 07:29 pm »

I modded my GTX2 with >> THESE << fans.

Frank gave the recommendation in >> THIS << thread. The fan specifics are on page two.

Works great, highly recommended.
Not sure how the unit is 'smart' enough to know you've been modding, unless it's an amperage issue.

Bob

JDUBS · « **Reply #8 on:** 24 Apr 2011, 01:27 am »

Quote from: Bob in St. Louis on 23 Apr 2011, 07:29 pm

I modded my GTX2 with >> THESE << fans.

Frank gave the recommendation in >> THIS << thread. The fan specifics are on page two.

Works great, highly recommended.
Not sure how the unit is 'smart' enough to know you've been modding, unless it's an amperage issue.

Bob

Yes, those are the exact same fans I linked to above. The GXT3 is "smarter" than the GXT2 in that it is able to control the fan speed based on the internal temperature of the UPS.

If someone with computer hardware expertise can take a look at this thread and let me know how an MB can detect a fan, I would appreciate it.

Thanks,
Jim

Bob in St. Louis · « **Reply #9 on:** 24 Apr 2011, 01:34 am »

Whoops, sorry....
Thought I'd be helpful. You're gonna need somebody smarter than me at this point.

JDUBS · « **Reply #10 on:** 24 Apr 2011, 03:02 am »

Quote from: Bob in St. Louis on 24 Apr 2011, 01:34 am

Whoops, sorry....
Thought I'd be helpful. You're gonna need somebody smarter than me at this point.

No worries...that thread of yours got me hooked on the Lieberts! I'm sure there is something I'm overlooking with the GXT3, I just need a little guidance.

Jim

Tam Lin · « **Reply #11 on:** 24 Apr 2011, 12:45 pm »

Quote

If someone with computer hardware expertise can take a look at this thread and let me know how an MB can detect a fan, I would appreciate it.

http://www.analog.com/library/analogdialogue/archives/38-02/fan_speed.html

Bob in St. Louis · « **Reply #12 on:** 24 Apr 2011, 02:53 pm »

Yea, same here. Franks suggestion of the Lieberts was priceless. I'l an official Liebert fanboy now. haha

Good luck man, I'm sure one of the gurus around here will guide you to a solution.

Maybe if it was me, I might start by looking for an electrical difference in the fans themselves. Maybe throw an ohm meter on them to see if there's a difference there.

Bob

fly_fish_nz · « **Reply #13 on:** 24 Apr 2011, 03:20 pm »

Are you sure the problem is with one or both of the fans? I think on the GXT3 the A,B indicators could be other issues as well, for example that the batteries are not charging. Just a thought, but could it be something as simple as the battery contacts were not perfectly aligned when you put them back in?

I am interested in replacing the fans in a GXT model. Are there any step by step info. that anyone has seen...pics would be great, since I don't want to electrocute myself on a weekend!

Bob in St. Louis · « **Reply #14 on:** 24 Apr 2011, 03:44 pm »

Quote from: fly_fish_nz on 24 Apr 2011, 03:20 pm

I am interested in replacing the fans in a GXT model. Are there any step by step info. that anyone has seen...pics would be great, since I don't want to electrocute myself on a weekend!

Not too much step by step involved. All you have to do is "pop the hood", remove the old fans and put the new ones in. If memory serves, I had to cut the connectors off the old fans and solder them on the new fans.
There wasn't much "dissassembly" as far as the machine is concerned. The only thing in the way was the flimsy white plastic ductwork seen on the right side of the top picture. In relation to the pic, there's a fan on the upper right corner (under the plastic), and one peeking out of the lower right corner of the plastic.

Note, the large open void on the left. That's where the battery pack slides out. The large wires on the lower left connect to the UPS.

Different models may vary, of course.
Hope that helps.

fly_fish_nz · « **Reply #15 on:** 24 Apr 2011, 06:44 pm »

Thanks Bob! Are the wires you refer to (that "connect to the UPS") for the fans, and did you detach them from the power supply before snipping near the fan? I also notice six capacitors in your pic - after I remove the batteries, is that all I have to avoid to stay safe? Thanks again.

Chris

Bob in St. Louis · « **Reply #16 on:** 24 Apr 2011, 07:06 pm »

You're welcome Chris.

The large red and black wires (10 gauge?) connect the battery pack to the UPS itself. Those wires are larger diameter then average lamp cord is.
The wires that connect the fans are more like 20 guage (very small). Much like phone wire or doorbell wire.

The unit must be unplugged from the wall, and the battery removed before digging around in there, although the bank of capacitors and the circuits they're connected to can still knock you into next week if you're not careful.

With all due respect Chris, I'm getting the impression you may not be to confident/knowledgable about what inside?
Rule number one for digging around in here is keep one hand behind your back while touching things. There's __NO__ reason to have both hand inside the chassis while performing then fan swap.

Maybe lay a small handtowel across the center of the unit, just in case.

Be careful.

Bob

fly_fish_nz · « **Reply #17 on:** 24 Apr 2011, 07:58 pm »

Thanks Bob. You're right - I haven't opened the chassis up or even disconnected the batteries yet, so my knowledge of what's inside is limited. In fact my general knowledge of electrical matters is limited compared to most of you guys - I'll take the precautions you mention and hope to stay in the current time zone.

Bob in St. Louis · « **Reply #18 on:** 24 Apr 2011, 08:18 pm »

Good deal.
My knowledge of what's going on in here is just a hair better than, "those round things sticking up can hurt me", so I'm a bit nervous giving advise to someone less skilled than I.

Time for the smart guys to chime in.
Sorry JDUBS if we've OT'd your thread.

Bob

JDUBS · « **Reply #19 on:** 25 Apr 2011, 01:15 am »

Bob, no worries at all! Hopefully this thread helps some folks out.

The fan thing is bizarre....no issue when I had my GXT2.

Also, I definitely checked all connections and took out the batteries and reinstalled them. Same issue each and every time I've fooled with it! Driving me nuts.

-Jim