Liebert GXT3 UPS Fan Question

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Bob in St. Louis

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Re: Liebert GXT3 UPS Fan Question
« Reply #20 on: 25 Apr 2011, 01:45 am »
Just for grins, put the OE fans back in, just to see....ya know?

Bob

JDUBS

Re: Liebert GXT3 UPS Fan Question
« Reply #21 on: 22 Jul 2011, 12:30 am »
Guys, to follow up on this.  I confirmed with Liebert that the unit looks for a particular resistance to know that the (stock) fans are in place.  They wouldn't give me the resistance number and I couldn't get a reliable number from my multimeter (still not sure why). 

Based on this, you WILL get a fan fault if you try different / quiet fans in the GXT3.  No issues with the GXT2.  I.e., if you want a Liebert, go with the GXT2.

-Jim

Bob in St. Louis

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Re: Liebert GXT3 UPS Fan Question
« Reply #22 on: 27 Jul 2011, 09:00 pm »
Good information Jim, thanks for the research.

Does anybody know if the OE fans on the GTX3 are as loud as the OE fans on the GTX2?

Bob

fly_fish_nz

Re: Liebert GXT3 UPS Fan Question
« Reply #23 on: 27 Jul 2011, 09:20 pm »
Good information Jim, thanks for the research.

Does anybody know if the OE fans on the GTX3 are as loud as the OE fans on the GTX2?

Bob

Bob,

Based on the environmental data in the user manuals, the GTX3 produces about the same noise at one meter as the previous models, between 40 and 45 db.  In my case, the original fans were much too loud to have in my listening room, but are not noticable from listening spot now that I replaced with quiet fans. 

JDUBS

Re: Liebert GXT3 UPS Fan Question
« Reply #24 on: 27 Jul 2011, 09:30 pm »
Bob,

Based on the environmental data in the user manuals, the GTX3 produces about the same noise at one meter as the previous models, between 40 and 45 db.  In my case, the original fans were much too loud to have in my listening room, but are not noticable from listening spot now that I replaced with quiet fans.

Did you do replace the fans on the GXT3?

Bob, the GXT3, stock, is about as loud as the GXT2.

-Jim

Bob in St. Louis

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Re: Liebert GXT3 UPS Fan Question
« Reply #25 on: 27 Jul 2011, 09:42 pm »
Thanks guys!
40-45? Wow, mine seemed soooooo much louder.  :o

Bob

fly_fish_nz

Re: Liebert GXT3 UPS Fan Question
« Reply #26 on: 27 Jul 2011, 10:31 pm »
Jim,
I replaced fans on a GXT 1500 ERT (extended run time) that I found locally with almost new batteries, and did not have any problem with an alarm after the swap. 

Bob,
Mine sure seemed louder than 45 db as well, so perhaps they get louder with age.  I can not hear the new fans, which are rated at 16db I think, from my listening area, but can still hear them if I get within a few feet of the UPS.  In any case, Liebert's tests are done in a controlled test with new units, so it does allow you to compare between the different models.

Bob in St. Louis

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Re: Liebert GXT3 UPS Fan Question
« Reply #27 on: 27 Jul 2011, 10:38 pm »
Good point fisherman, thanks for the info.  :thumb:

Bob

JDUBS

Re: Liebert GXT3 UPS Fan Question
« Reply #28 on: 27 Jul 2011, 10:40 pm »
Jim,
I replaced fans on a GXT 1500 ERT (extended run time) that I found locally with almost new batteries, and did not have any problem with an alarm after the swap. 

Bob,
Mine sure seemed louder than 45 db as well, so perhaps they get louder with age.  I can not hear the new fans, which are rated at 16db I think, from my listening area, but can still hear them if I get within a few feet of the UPS.  In any case, Liebert's tests are done in a controlled test with new units, so it does allow you to compare between the different models.

I "think" the only problem Liebert is the GXT3.  The GXT and the GXT2 seem to take to the fan replacement fine.

-Jim

fly_fish_nz

Re: Liebert GXT3 UPS Fan Question
« Reply #29 on: 27 Jul 2011, 11:27 pm »
I "think" the only problem Liebert is the GXT3.  The GXT and the GXT2 seem to take to the fan replacement fine.

-Jim

I think you are right and can at least confirm that the GXT1500 accepts new fans without a hitch.  Sorry to hear that the GXT3 is problematic for you - what a bummer to go through the hassle of buying, shipping the UPS, and then swapping fans only to find that the alarm causes problems.  I wonder if Liebert could help you disable the alarm.  On my unit I am able to disable alarms with just two exceptions, i.e., they cannot be disabled when in bypass or battery modes.  Having the alarms run in those circumstances seems like a good idea, because in the first equipment is not protected from disturbances in the mains power line, and in the second I don't wan't to drain the batteries before I've turned off the equipment.

Bob in St. Louis

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Re: Liebert GXT3 UPS Fan Question
« Reply #30 on: 27 Jul 2011, 11:59 pm »
If it's a resistance issue, couldn't a fellow add some resistance to the circuit?

Bob

Codec

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Re: Liebert GXT3 UPS Fan Question
« Reply #31 on: 1 Dec 2019, 10:59 am »
I know this is tread is very old but it is the top result in google for fan swapping for a gxt3. I added two 20 ohm 10w resistors in series across the rear fan connection along with changing both fans for some Arctic P8 and everything works fine and is MUCH quieter now. Im sure just one 40 ohm resistor would work so long as its rated for at lest 5w will work but 20 ohm ones on amazon are cheap and just helps spread the heat. I epoxied both of them to a magnet and stuck it right in front of the rear fan. That way it has air flow and heat can sink though the magnet and into the case. One thing to note is the usp only monitors the rear fan it seems so you only need to add resistors to that one.

lukyjay

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Re: Liebert GXT3 UPS Fan Question
« Reply #32 on: 24 Jul 2020, 07:25 am »
I know this is tread is very old but it is the top result in google for fan swapping for a gxt3. I added two 20 ohm 10w resistors in series across the rear fan connection along with changing both fans for some Arctic P8 and everything works fine and is MUCH quieter now. Im sure just one 40 ohm resistor would work so long as its rated for at lest 5w will work but 20 ohm ones on amazon are cheap and just helps spread the heat. I epoxied both of them to a magnet and stuck it right in front of the rear fan. That way it has air flow and heat can sink though the magnet and into the case. One thing to note is the usp only monitors the rear fan it seems so you only need to add resistors to that one.

Hi

Thank you so much for this information. I have done what you've suggested by wiring two, 20ohm 25w resistors in series on the black wire of an Arctic P8 fan, and installed it onto the rear fan header. The front fan header has a P8 directly connected since you mentioned only the back needs resistors.

I'm still getting the fan error however. Any ideas what I may have done wrong? I checked the resistors with a multimeter and they were 20ohm each, 40 when connected.

Appreciate your support since like you mentioned there's nothing else on Google related to fan replacement on this UPS.