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psannz
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CSS326-24G-2S+ & active cooling

Thu Jun 08, 2017 9:56 am

Hi all,

I have been having mixed results with a few CSS326-24G-2S+ running SwOS 2.1 and 2.2. After 10 to 12 days, they would stop forwarding traffic and all connected devices would stop showing an active connection.

Seeing as the switch shows 60-61 °C temperature running idle I was wondering if it would help with stability if I added active cooling.
The cut out for a 40mm fan is already there, as is an accessible 24V rail (J2) next to the power connector (J1).

The plan was to install a EBM Papst 414 or 414F (1W power req.), add a shroud, and have it blow air on the chips.

What do you folks think? Worth the effort?
 
aboiles
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Re: CSS326-24G-2S+ & active cooling

Sat Jun 10, 2017 6:35 pm

I am interested in your modification, my CSS326 is usually running about 69-70c.
Please let me know your results.
 
psannz
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Re: CSS326-24G-2S+ & active cooling

Wed Jul 12, 2017 3:27 pm

Alright, time for results.

First of all: The 40mm fan cutout in the back is loud as hell. If you want to avoid noise you'll have to either remove the cutout as a whole or place the fan further inside the case.
I ended up placing the fan, indeed an ebmpapst 414, next to the system board. If you look a the bottom of the case you'll see a hole that you can use as a start for the fixings. That way, combined with a little shroud, the fan is blowing directly onto the little black heat sink and further down the big aluminium one.

As powersource I ended up using the empty J2 connector. Biggest downside: No power if the switch is running on pure PoE power, i.e. no PSU connected to J1 connector.
In my case it's good enough, as I only use the PoE input as backup supply.
I did add a 330 Ohm resistor, to reduce fan speed and power draw. That way it's quiet enough to use in the open in the office without users complaining about the noise.

Right now, the switch has been stressed for 3 days with a constant 21-22 Gbit load and I have yet to see the temperature sensor report more than 43°C, at an ambient temperature of 23-24°C. Idle is around 36-38°C.

All in all I'm content with the mod.
 
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normis
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Re: CSS326-24G-2S+ & active cooling

Tue Jul 18, 2017 9:14 am

The reason could be elsewhere. The CSS326 is tested for up to 65C AMBIENT temperature. The temperature reported by the sensor can easily be above that and have no effects. How about the SFP modules, maybe they have lower supported temperature? What is the ambient temperature in your room?
No answer to your question? How to write posts
 
psannz
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Re: CSS326-24G-2S+ & active cooling

Tue Jul 18, 2017 9:42 am

The reason could be elsewhere. The CSS326 is tested for up to 65C AMBIENT temperature. The temperature reported by the sensor can easily be above that and have no effects. How about the SFP modules, maybe they have lower supported temperature? What is the ambient temperature in your room?
Ambient room temperature was 22-23°C, in the 19" rack it get's up to 28-29°C. Highest i ever measured inside the rack via network thermometer probe was 31°C.

SFP modules in use are Finisar FTLX8571D3BCL, which should be good up to 70°C. Right now both are running at 35 and 36°C.

In the end, my issues of instability might have come from the old firmware. Deployed both the fan mod and the upgrade to version 2.3 at the same time, so I'll never know.
 
Kaldek
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Re: CSS326-24G-2S+ & active cooling

Thu Jan 30, 2020 6:01 am

I have a CSS326 (SwOS 2.10) running currently at 85C (!!). I only noticed because my RJ45 SFP+ module started to drop packets and when I went to remove the module it was frikkin' red hot. I moved the Cat6 cable to a spare 1Gb/s port which brought back connectivity but HOLY COW - 85C on the mainboard and a red hot SFP module??

This is home use and is located in a 19" network rack on the wall in my garage. It's hot here today - 33C but all my other network gear is fine including the RB3011 router which is located just below the CSS326. The RB3011 is running at 45C which is of course perfectly fine.

If I blow air into the back of the CSS326 using an air wand on an air compressor the temperatures drop down to the mid 60s.

I'm guessing I'm going to need to stick a heat sink on top of the SFP cage inside the case, and add some active cooling?
 
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Lifz
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Re: CSS326-24G-2S+ & active cooling

Thu Jan 30, 2020 9:01 am

Did you read S+RJ10 general guidance?
https://wiki.mikrotik.com/wiki/S%2BRJ10 ... l_guidance
 
Kaldek
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Re: CSS326-24G-2S+ & active cooling

Mon Feb 03, 2020 3:23 am

Did you read S+RJ10 general guidance?
No, as this is a Ubiquiti branded SFP+ module (it was cheaper here in Australia than the Mikrotik unit). However the same problem described for the Mikrotik model as per the general guidance page applies. The product page for the S+RJ10 module now also says it's only suitable where there's active cooling in use.

I will be adding a cooling fan to my CSS326 and sticking heat sinks to the accessible parts of the module itself as well as one to the SFP+ cage inside the case. I have some of the correct style of heatsinks available.
 
Kaldek
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Re: CSS326-24G-2S+ & active cooling

Fri Feb 07, 2020 5:21 am

Holy CARP! I just fitted a 2 watt 40mm 24V fan to the back of my CSS326 and the reported temperatures dropped from 70C down to 38C!
Those are *stellar* results. I've already fitted heat sinks to my SFP+ module, so let's see if the additional air flowing over the SFP cage (practically opposite the fan) helps as well.

The fans I chose are NMB 12608KL-05W-B39 units and are very quiet even pushing air through the fan cutout in the case. I was concerned that I would perhaps need to check and re-apply the thermal compound to the heatsinks on the chips, but with these results I'll be skipping that and also not bothering with attaching heatsinks to the SFP cage.
 
Kaldek
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Re: CSS326-24G-2S+ & active cooling

Thu Feb 20, 2020 7:29 am

It's been a few weeks and my switch has maintained low temperatures under 50C in all circumstances. I have permanently fitted the fan to the switch and also ducted the air so that it blows towards the SFP cage. I did not need to remove and re-seat any heatsinks or change thermal paste/glue to achieve these results.

I consider this a permanent solution to managing heat in the CSS326 chassis.
 
ilkogd
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Re: CSS326-24G-2S+ & active cooling

Wed Mar 18, 2020 10:23 am

My experience with CRS326-24G-2S running RouterOS - I buy first unit 6 months ago and start using it actively from the first date. The temperature reported in System Health was always above 70 degrees. Most of the time between 73 and 76 degrees. I use the switch ONLY for L2 so the CPU don't handle any traffic. Yesterday I buy second unit and this time decide to put fan inside. After the modification, today I swap the old unit with the new one. Now reported temperature in System Health is 48-52 degrees and the temperature of SFP optical module is 40-42 degrees. Inside the rack the temperature is 26 degrees. I think this is perfectly fine, so I will modify and the old unit before put it in production next week.

What I did:
- buy 40mm ball bearing 24V DC fan Evercool EC4020H24BA
- use J2 connector on the board to feed with power the fan
- also solder one 120 ohm resistor on the "+" wire to lower a little bit the voltage, the fan is running on 20V now

I don't know why the CPU is running so hot even when there isn't any L3 traffic on the switch, maybe the heat sink is very small for passive cooling.
Image
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incagarcilaso
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Re: CSS326-24G-2S+ & active cooling

Thu Feb 11, 2021 10:13 am

Holy CARP! I just fitted a 2 watt 40mm 24V fan to the back of my CSS326 and the reported temperatures dropped from 70C down to 38C!
Those are *stellar* results. I've already fitted heat sinks to my SFP+ module, so let's see if the additional air flowing over the SFP cage (practically opposite the fan) helps as well.

The fans I chose are NMB 12608KL-05W-B39 units and are very quiet even pushing air through the fan cutout in the case. I was concerned that I would perhaps need to check and re-apply the thermal compound to the heatsinks on the chips, but with these results I'll be skipping that and also not bothering with attaching heatsinks to the SFP cage.
Hi Kaldek. I am looking at doing the same, with board at 70 constantly and SFP modules at 87! I don't like having equipment running at these temperatures and they will only rise further with the summer temperatures later on.
Can you help a little with the procedure? Does the fan you mention come with the correct connector to just plug into the board? Which connector is it on the board? Also, how did you attach heatsinks to the SFP modules exactly. Any help on the procedures would by very much appreciated.

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