Noisey Dometic refrigerator fan

[IBcarguy]

The refrig in our TT is in a slide-out that vents out the back side of the unit. The fan is quite noisey and I've read a lot of people have complained about the noise level, it's a common problem.
The fan is 92mm, 4500 rpm, 75.0 cfm, 47 db 12v fan. There are a million fans available with a million different specs. There's room to put in a larger a 120mm fan, but which one do I try? The current fan goes on quite often and runs a long time so I don't want to reduce the air volume for the sake of noise. Has anyone found a specific fan that will provide the air flow yet is quiet?

[SCVJeff]

The gold standard for quiet fans is NOCTUA.. Allot of them are IP65 rated, 100,000hr MBTF, far better than most out there. Look at the website at what they have.

I run 4 of them turning at <50% and it has to be desert silent to hear them running at all, and all 4 running at this speed pull slightly more than just one.

[landyacht318]

By all means, use more, larger slower quieter fans if you have the room to do so.

That 4500 rpm 92Mm fan likely draws -.7 amps

I have a vantec tornaldo 92mm fan at 0.8 amp and 4800 rpm and claims to move 119CFM. Very loud and powerful.

So 4500 rpm lets say 100cfm. If the designers who installed the loud 92MM fan determined 100CFM is required, and there is room for 2 120MM fans.

The Noctua NF-f12 together would move ~106CFM for 0.1amps

BUt they are a pricey fan. They do come with 'noise reduction cables (resistors) to run at 2 lower speeds

Lots of 120MM fans though.
http://www.frozencpu.com/products/14423/fan-922/SilenX_120x120x25mm_-_15dBA_-_74CFM_Effizio_Series_Q...

Honestly the Silverstone fans with speed control are just plug and play. YOu could duct tape the potentiometers and their wiring in the general area, dial them to a lower speed in winter, and crank them up in summer when loading the fridge down. You can also relocate them about 3 feet from the fan itself, or further if you want to splice in more wire

The silverstone FM121 is quieter on full speed 2400 rpm, than my 4800 rpm 92Mm fan, and draws half the amperage for nearly the same cfm rating.

For noise and efficiency at 100CFM, 2 noctua nf-f12's would be hard to beat at just 0.1amp.

If battery consumption is a consideration.

[grizzzman]

IBcarguy wrote:
Landyacht318 - Thanks for the input. I'd give the Silverstone fm 121 a try but I don't want to mess with variable speed. I am actually considering setting up 2 fans. My thinking is 2 lower speed fans with less noise might push more air than 1 high speed fan.

Bingo!!!!!!!

[fj12ryder]

When my fan started making noise I replaced it with 2 fans of the same size. I got them off Ebay, low amperage draw, move a decent amount of air, and waterproof. I don't hear them at all when they are running.

[IBcarguy]

Landyacht318 - Thanks for the input. I'd give the Silverstone fm 121 a try but I don't want to mess with variable speed. I am actually considering setting up 2 fans. My thinking is 2 lower speed fans with less noise might push more air than 1 high speed fan.

[landyacht318]

Try the silverstone fm 121
120MM and variable speed adjustable via a small potentiometer.

110CFM on high at about 0.4 amps, about 32cfm on low at about 0.09amps.

Dial a speed, dial a noise level.

If you want more of a set it and forget it fan, then try an industrial Noctua.

https://www.amazon.com/Bearing-NF-F12-iPPC-2000-PWM/dp/B00KFCR5BA

I have the 1500 rpm version (~53cfm, 0.05 amps)of that fan. It is very quiet and has been on my compressor fridge for 4+ years and works better than the original 72cfm fan.

BIgger fans are generally quieter for the amount of air moved.

High RPM fans are good for higher static pressure ratings, meaning they push air through and around obstacles better.

Noctua fans have high static pressure ratings considering their quietness and generally lower cfm ratings.

My favorite computer fans are from Delta, Noctua, Silverstone and Vantec. I've worn out a few Silverstone fans over the last decade, some have failed due to circuit board corrosion due to a salt air environment.

I will be getting Noctua Industrial fans from here on out and controlling their speed via PWM signal by the fourth wire as I feel they are top dog in static pressure, cfm, noise, and electrical consumption.

[Jay_Pat]

Sound/white noise, sound machine. Turn it up enough to drown out fan.
Greatly helps with other outside noises.
Pat

[ScottG]

Those kinds of fan are always a trade off. More flow for a given size = more noise.