SMX2200RMHV2U fan replacement

satanski Member

Hello forum,

I bought a second hand SMX2200RMHV2U where the fan noise is constant when it's on. According to this FAQ, the SMX should use variable speed fan.

I opened up my unit and found the following fans:

- Sunon EE80252B1-0000-A99 41CFM
- Y.S.TECH NYW08025024BSS 59.2 CFM

I have a feeling the fans are replacemen fans, as they only have GND and +24DC cable going to a 3 pin connector. The control board has 3 pins, I haven't yet measured what the third pin is for, but I would think it's a tach input signal?

Does anyone know what the original fans are for this unit? Schneider support doesn't want to comment on it.

Or if anyone knows if the third pin is for Tach, then I will obtain fans that match the CFM but also provides tach.

Thanks in advance

satanski, 2025-03-08 11:49:42 +00:00

#127
NB-23 Member Warrington

Howdy

I think you are OK going for similar power (either CFM or roughly going on voltage x current).
We sometimes have scrap units that have OK fans
If you cant find decent fans from somewhere then contact us and we'll leave a note to email you when we next get some.

My feeling is that changing the fans is not going to change the fan behaviour on the UPS - I think you are aiming to have the fans slow/stop or just be less noisy.

Depending on load / ambient temperature we have had customers experiment with quieter fans but you are off into the unknown with that so you need to test seriously to make sure it does not overheat.

NB-23, 2025-03-10 10:02:21 +00:00

#128
satanski Member

"NB-23" said:

Howdy

I think you are OK going for similar power (either CFM or roughly going on voltage x current).
We sometimes have scrap units that have OK fans
If you cant find decent fans from somewhere then contact us and we'll leave a note to email you when we next get some.

My feeling is that changing the fans is not going to change the fan behaviour on the UPS - I think you are aiming to have the fans slow/stop or just be less noisy.

Hi NB-23,

Thanks for taking the time and helping me!

I've gone for this fan: https://uk.rs-online.com/web/p/axial-fans/2025435, 60CFM, and it seems to be a tiny bit more quiet.

However, my confusion is why the fans are running at full speed, continuously even when there is less than 70W load and batteries are fully charged. They never change speed, from my understanding, the SMX units should adjust speed depending on demand, but this doesn't seem to be the case.

Have you come across SMX units that use the third fan pin on the controller board? This must be tach signal right?

satanski, 2025-03-11 18:55:58 +00:00

#131
NB-23 Member Warrington

Nope!
I've just gone to check a UPS in stock and both fans are none tacho 2 pin type. They must be driven on a temp/load map.
The unit I have is sitting idle and the fans are completely stopped.
As before I dont think changing your fans is going to change that yours are on full all the time.

Let me send the photos of the unit.

NB-23, 2025-03-12 09:35:43 +00:00

#132
satanski Member

Thank you!

That's so strange, I wonder what's causing my unit to have the fans blow at full speed.. I wonder if bad batteries can cause this?

I haven't seen any configuration which would change this behaviour either

satanski, 2025-03-12 10:49:45 +00:00

#133
NB-23 Member Warrington

I dont think its the batteries.

There is a risk in flashing the firmware but you could give that a go. I think something in the UPS has gone bad, but in a none critical way to normal use.

NB-23, 2025-03-12 11:16:21 +00:00

#134

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satanski Member

NB-23 Member Warrington

satanski Member

NB-23 Member Warrington

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