Noisy fan on new Dometic fridge

[DavidG58]

we swapped our fridge for a massive unit that replaces the full height of the Tec tower with a 2 section fridge

The lower section is a pull out drawer designed to hold bottles upright, it is cooled by fans in the upper section blowing air downwards, that is the only cooling option but it seems very efficient I have checked it at 3C on 2 occasions

The problem in ours is the fan is noisy, not all the time but more often than not, sounds a bit like a computer fan about to pack in

I had thought it was a design issue with food pushing against the back plate, today I have taken the back panel off fir a look

My theory on computer fans would seem well founded but my theory of pressure from back plate is unfounded

But by sheer luck when I pulled the back plate off the noise stopped, both fans are now spinning but they are the most feeble things ever, no doubt will need to be changed annually or more often so I have not screwed the plate back on so I can have easy access when needed next

I will try and get a photo of the label on the fan

 

[DavidG58]

Photo of label on back of fan, hopefully a fraction of the price for a Dometic spare part

Possibly left on by mistake the second one has no label

Not easy to photograph in the blue light zone

 

[Two on Tour]

I used this company for my fridge vent fans as they give info on noise and how much air they push for each fan listed.

https://www.quietpc.com/casefans

 

[Guigsy]

40mm fans make a horrible noise!

In the PC world, people hate 40mm fans. The general rule is, get some quality branded quiet ones... but try to fit bigger if you can. Bigger diameter means more area, so they can spin slower for the same air flow, which means less noise.

 

[pappajohn]

Not easy to photograph in the blue light zone

Dead easy.... Turn the fridge off and use the flash on your phone/camera if needed.

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[Wissel]

Noctua make a few very good quiet 40mm fans.

 

[DavidG58]

40mm fans make a horrible noise!

In the PC world, people hate 40mm fans. The general rule is, get some quality branded quiet ones... but try to fit bigger if you can. Bigger diameter means more area, so they can spin slower for the same air flow, which means less noise.

Trouble is I would need a new back plate to fit anything bigger, or a better DIY ability than mine at least

Nice thing or lucky for now at least it has gone nice and quiet again

 

[DavidG58]

Made an interesting observation today, while working on the much quieter but occasionally noisy fan

On the photos above you can see only one fan has a label

I now know they they both have labels albeit different to each other but the one showing with no label was in fact in backwards , or at least the other way round to its mate

I now don’t know if that was deliberate, one blowing cold air in, the other drawing it back out maybe?

For now I am going to try it with both blowing into the lower section and check the temperatures to see if better or worse or most likely no different

 

[Robert Clark]

How about spraying the fan with a little silicone?

 

[DavidG58]

How about spraying the fan with a little silicone?

Can’t believe I haven’t thought of that myself

Another observation made today though, if I slide the fan out it’s housing and lay it down flat, it is quiet, I wonder if they are not designed to be fitted vertically?

Off out with spray now, it is only one that is noisy, so maybe buy a new fan the same as the one that is silent will fix it for a few £

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[dalspa]

Made an interesting observation today, while working on the much quieter but occasionally noisy fan

On the photos above you can see only one fan has a label

I now know they they both have labels albeit different to each other but the one showing with no label was in fact in backwards , or at least the other way round to its mate

I now don’t know if that was deliberate, one blowing cold air in, the other drawing it back out maybe?

For now I am going to try it with both blowing into the lower section and check the temperatures to see if better or worse or most likely no different

Could it be intentional with one sucking and the other blowing , so as to create a circulation of cold air?

 

[Treeeev]

Can’t believe I haven’t thought of that myself

Another observation made today though, if I slide the fan out it’s housing and lay it down flat, it is quiet, I wonder if they are not designed to be fitted vertically?

Off out with spray now, it is only one that is noisy, so maybe buy a new fan the same as the one that is silent will fix it for a few £

David

It could be that the fan is being distorted when it is tightened up, causing the noise. Try it only lightly tightened to see if that makes a difference

Cheers

Trevor

 

[DavidG58]

David

It could be that the fan is being distorted when it is tightened up, causing the noise. Try it only lightly tightened to see if that makes a difference

Cheers

Trevor

They are slotted in to the plastic front plate, but your logic is good because when removed from the frame they are silent

The WD40 has improved things but not cured yet

2 x new fans ordered

 

[tonyidle]

Looking at the duct design they should both work in the same direction. If the fan is noisy because it lacks lubrication the bearing is behind the label - peel it off & use 3 in 1 oil or similar. WD40 is not a lubricant. I'm not sure where you sprayed WD40 but if it was into the motor behind the blades it will collect dust & the fan will fail - all that's in there is windings & electronics. The fans can be mounted at any angle. If noise continues to be a problem try mounting the fans on sticky foam pointing directly down the holes at the back.

 

[DavidG58]

Looking at the duct design they should both work in the same direction. If the fan is noisy because it lacks lubrication the bearing is behind the label - peel it off & use 3 in 1 oil or similar. WD40 is not a lubricant. I'm not sure where you sprayed WD40 but if it was into the motor behind the blades it will collect dust & the fan will fail - all that's in there is windings & electronics. The fans can be mounted at any angle. If noise continues to be a problem try mounting the fans on sticky foam pointing directly down the holes at the back.

Thanks for that input

I think it is just a bad fan, odd that they don't match already, maybe one has already been swapped, we bought this as a returned second at much reduced price, the noise really isn't that bad until the door is opened and acts as a reminder to close it quickly

I have ordered 2 new fans and I am also thinking about fitting a bigger fan with a light in the lower section, that would overcome a no light in that section and possibly avoid the need for the little fans altogether

At less than £10 each this will be by far the cheapest repair I have done to date

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[tonyidle]

Thanks for that input

I think it is just a bad fan, odd that they don't match already, maybe one has already been swapped, we bought this as a returned second at much reduced price, the noise really isn't that bad until the door is opened and acts as a reminder to close it quickly

I have ordered 2 new fans and I am also thinking about fitting a bigger fan with a light in the lower section, that would overcome a no light in that section and possibly avoid the need for the little fans altogether

At less than £10 each this will be by far the cheapest repair I have done to date

I'm slightly confused by the photo. What is below the fans? I'm assuming the vertical 'duct' walls direct the output (or input?) of the fans towards the oval holes. Where does the other side of the fan go?

 

[Brendan]

David, having learnt from the guru @DavidG58 I try not to post after alcohol consumption, but by tomorrow I will have forgotten all these important points.
Having heard the racket from your new cooler I have to say while I agree the noise is caused by the fans, I suspect that just replacing them is not the solutiion, if that's not too silly.
What you are getting is a vibration noise, possibly from something as silly as one of those little wires vibrating against the panel you removed, or much more likely that panel itself just hitting a resonant frequency.
I know you have already ordered new motors, but the easiest thing may be to try a very light self adhesive weight on the plastic panel.

 

[Debs]

David, having learnt from the guru @DavidG58 I try not to post after alcohol consumption, but by tomorrow I will have forgotten all these important points.
Having heard the racket from your new cooler I have to say while I agree the noise is caused by the fans, I suspect that just replacing them is not the solutiion, if that's not too silly.
What you are getting is a vibration noise, possibly from something as silly as one of those little wires vibrating against the panel you removed, or much more likely that panel itself just hitting a resonant frequency.
I know you have already ordered new motors, but the easiest thing may be to try a very light self adhesive weight on the plastic panel.

Brendan that's a very sensible post alcohol post, I'm impressed

 

[Brendan]

Brendan that's a very sensible post alcohol post, I'm impressed

Cheers, Debs.
I thought I was doing well just remembering the code for my phone.

 

[Debs]

Cheers, Debs.
I thought I was doing well just remembering the code for my phone.

Sounds like a proper session perhaps that's a potential solution for David if he can't sort the fans, get p*ssed whenever he's away. .... Oh hang on a minute

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[DavidG58]

I'm slightly confused by the photo. What is below the fans? I'm assuming the vertical 'duct' walls direct the output (or input?) of the fans towards the oval holes. Where does the other side of the fan go?

I think Brendan has got the fault

Photos of layout below, as you thought fans draw air through into the channels and out into the roof of the lower drawer section which has no cooling other than this air, but is remarkable efficient

The fans slide into a frame in the plastic cover and when removed the noisy fan is silent, whichever way up I hold it, swapped from one side to the other and it is still noisy when fitted but the other one is silent in both sides

So although it is only noisy when fitted I have confidence that a different fan will solve the problem, I have for now disconnected the noisy one, all now quiet and as the noisy one had in fact been fitted to blow air out it will not make much difference with only the single fan

 

[andy63]

Hi David .. I haven't studied the thread in detail and hope you can sort the noisy fan out..
When you said you thought one fan was mounted the wrong way round i was surprised as looking at them i assumed that they were there purely to circulate air in that compartment and would expect one to suck and the other to blow... do you not think that's the case??
Andy..

 

[DavidG58]

Hi David .. I haven't studied the thread in detail and hope you can sort the noisy fan out..
When you said you thought one fan was mounted the wrong way round i was surprised as looking at them i assumed that they were there purely to circulate air in that compartment and would expect one to suck and the other to blow... do you not think that's the case??
Andy..

Thanks Andy


It might be a design idea to have one blowing and the other sucking, that was how we found it, oddity was they were different makes of fan

Easy enough to swap round anyway so can try both combinations to see which is most efficient , once I have 2 fans that I can use that is

 

[funflair]

I know I am late to this as well. First off I am impressed with how “hands on” David is getting, second I am with @andy63 in that the fans need to circulate air rather than just pressurising the box with nowhere for it to which will just stall the cooling effect.

Martin

 

[tonyidle]

I know I am late to this as well. First off I am impressed with how “hands on” David is getting, second I am with @andy63 in that the fans need to circulate air rather than just pressurising the box with nowhere for it to which will just stall the cooling effect.

Martin

I think you're both correct too. I got hung up initially on moving cold air from fridge base to drawer. Which for the reasons stated by @funflair wouldn't work with both fans operating in the same direction.

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[dpsuk999]

I added a couple of fans to the top of my cooling fins last year and what a difference it made to the temperature at the bottom of my fridge. It circulates the air down over the cooling fins, taking with it the cold air. While I had the fins removed I also replaced the thermal paste too:

 

[Lenny HB]

The WD40 has improved things but not cured yet

Oh dear, if they have nylon sleeves on the shafts you have just buggered them. WD40 should never be used on nylon it makes it swell.

Sounds like it's up to the normal Dometic quality.

 

[DavidG58]

Oh dear, if they have nylon sleeves on the shafts you have just buggered them. WD40 should never be used on nylon it makes it swell.

Sounds like it's up to the normal Dometic quality.

Thankfully at £3.50 each it didn’t really matter as anew one was already on order , as it happens it neither killed the fan or cured the problem

 

[DavidG58]

All sorted, bought pack of three 40mm x 40mm x 10mm fans. Labelled Maplin, swapped one which I literally couldn’t hear running, now the original quiet one seems loud

So swapped both now barely audible

Doing a temperature check now, yesterday with only one fan flowing air in we only got down to 9C, but it was 35C inside MH

Today MH in shade now, will check in an hour to see how it has got on, started at 10C with me having door open

 

[DavidG58]

this is not going as well as I had hoped, been monitoring lower section temperatures, they are not getting much below 8C, not overly serious as most of content is tonic water

I have done some research into the fans originally fitted and what I have now bought, originals are not easy to track down even via google, but one of them quoted air movement of 5cuft/min, the ones I have preplaced them with are rated at 18cuft/min, surely they can't be too efficient

But I have also bought (by slight ebay purchase error ) another pair with lower air movement rate, I could fit them but am not convinced that will help

I have tried having both blowing in and alternated which side blows / sucks, no combination makes significant difference, not yet tried having both sucking out, but that seems silly

the only significant thing might be the MH is closed up and daytime temps are close to 30C inside, in real use we would have doors, windows and vents open that would keep down internal temps

we are also running solely on electrics, more updates will follow

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