# Fridge Ventilation Fans - They Work!



## krull (Jul 22, 2006)

I have the usual Electrolux 3 way fridge, When used for extended periods, no matter what the power source, it appears to lose interest after a few days, and doesn't cool like it should. The cooling unit was replaced last year under warranty, but didn't make a huge improvement. 

This year I made myself a cooling system:

Electronic thermosat kit from Maplins £5 (you have to solder it together).
120mm computer cooling fan from Maplins £6
A secret push on/off master swith that you operate by poking a knife through the cooling grill.

Tried it last week for 10 days and what an improvement, The themostat turns the fan on when the temp above the cooling fins reaches 30 degrees. 

I would recommend it. In our case the Fiamma handle parks across the vent grill which doesn't help.

However I will be making some alterations:
Fan is oversized (only runs for 10secs) and quite noisy, so will change it for a Maplins 80mm Ultra Quiet one


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## geraldandannie (Jun 4, 2006)

I like this idea. Thanks!

Gerald

_Edit:
:: Thermostat kit ::

:: Ultra quiet fan ::_


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## davesport (Nov 12, 2006)

Excellent post Krull.

Do you have the part numbers for the thermostat kit & 80mm fan ?

Kind regards Dave.


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## geraldandannie (Jun 4, 2006)

davesport said:


> Do you have the part numbers for the thermostat kit & 80mm fan ?


See my edited post, Dave :wink:

Gerald


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## Autoquest (May 16, 2007)

I would be very interested in this but how did you get access to the rear of your fridge?

Did you remove the fridge or can you remove the vents from the back and get in from there?


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## davesport (Nov 12, 2006)

G & D  

Thank you. 

Dave.


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## mangothemadmonk (Aug 6, 2006)

I use one of

These....

Brilliant bit of kit and they do make a difference.

Bit more expensive though.

Johnny F


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## Autoquest (May 16, 2007)

Are they easy to retrofit though?


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## DTPCHEMICALS (Jul 24, 2006)

For years i have used a simple 12 volt fan from halfords and a bracket made from mecano strips and use the grill screws to fix, the lead pasese thro a window and into a cigar lighter I disconnect over night
Cheers 
Dave P


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## andyman (Aug 31, 2006)

DTPCHEMICALS said:


> For years i have used a simple 12 volt fan from halfords and a bracket made from mecano strips and use the grill screws to fix, the lead pasese thro a window and into a cigar lighter I disconnect over night
> Cheers
> Dave P


Fred Dibnah would have been proud of you.


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## DTPCHEMICALS (Jul 24, 2006)

Uncle Fred,
another Great Briton, taught me all i know. We could do with some more like him.

Dave P


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## spykal (May 9, 2005)

Hi

I have seen fans fitted and all the users say how well the fridge works with one fitted... I do not have a fan fitted but I have arranged a simple deflector to guide the rising warmed air from the heat exchanger towards the outlet ...this too has improved the performance of the fridge and helps to keep the work surface and the cupboard above the fridge a little cooler than before I fitted it.


Mike


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## Zebedee (Oct 3, 2007)

Autoquest said:


> I would be very interested in this but how did you get access to the rear of your fridge?
> 
> Did you remove the fridge or can you remove the vents from the back and get in from there?


The outside vents are usually only clipped into place with quarter-turn fixing clips. There's no sealant on mine either so they are easy to remove, and give plenty of access.

I may well fit a fan to my top vent, but shall drill through and fit a switch inside the van if I do. All for ease and convenience me - though Mrs Zeb calls it idleness!! 8O

Also I shall use a computer cooling fan. Cost pennies, designed to run continuously with very little power consumption, and already fitted with a hole at each corner for easier mounting.

If one is not enough it's dead easy to install another one in parallel, and they won't restrict the airflow much when they are not switched on.

Messrs Autosleeper already fitted a deflector (of sorts) as mentioned by Spykal, and they should really be fitted by all manufacturers IMO.


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## Texas (May 9, 2005)

My fridge is boxed in (as per John Wickershams' advice) from the rest of the van and it has a deflector to guide the hot air out of the top vent, we've also had 2 quiet running fans fitted to our top vent for the last 4 years.

They have built-in gizmos that allow the fans to run faster as the air over them gets hotter, If the air is cool they don't run. They cost £3.49 off ebay at the time. I have wired them to the leisure battery via a switch so that they can be switched off at night, or, when required. 

They are superb at extracting the hot air - 'tho you have to go outside to check that they are in fact running, they are so quiet - especially down at the Med.


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## pneumatician (May 1, 2005)

*Fridge fans*

I made up a similar system about four years ago after seeing the idea in the CAK tanks catalogue. Having loads of scrap Computer power supplies lying arround I used 3 fans from these. 
As you say they do work and the heat extracted is certainly significant.
I mounted mine in the top to pull the hot air out and cool air through.

Steve


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## bognormike (May 10, 2005)

I had this problem a while ago (3 years ago!)

http://www.motorhomefacts.com/ftopic-6666-0-days0-orderasc-hot.html

I had an exchange of PMs and one of the kind members (can't remember who :roll:  ) sent me a computer fan, which I fitted inside the top vent with a separate switch. I now put it on when the fridge struggles to cope - no problems since  8)


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## Chausson (Oct 17, 2006)

Hi

I have just purchased one of those thermometer kits that's talked of, I have assembled the kit but for the life of me I cant figure out how to use it, can someone please point me in the right direction to stop me going mad wondering how to wire the thing up. 

Ron :roll: :roll: :roll:


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## pippin (Nov 15, 2007)

Right Ron - pay attention!

I made my kit up this afternoon, have bench tested it but have not yet fitted it into the vents.

Make a short wire link and join the +12V terminal to the COM terminal.

Connect the +12V input wire to that same +12V terminal.

Connect the -12V (it isn't - it is zero volts really) input wire to the -12V terminal.

Connect the black lead to the fan to that same -12V terminal.

Connect the red lead to the fan to the NC terminal.

Turning the temperature control knob back and forth should make the fan stop and start.

Experiment with the knob setting when the fridge is on to get a feel of how hot you want it to get before the fan switches on.

E&OE


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## Chausson (Oct 17, 2006)

Hi Pippin

Thanks for the info, I would never have got there without the help, you izzz top man.

Regards Ron


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## Autoquest (May 16, 2007)

Thanks Zebedee


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## mark_2cv (Sep 13, 2006)

I have one of these fitted above the fridge freezer, and just behind the Smev oven and it works well, if a little noisy. 
I am thinking of changing the single fan for two "silent" models with a further mod which I would welcome opinions on - 

The oven has a frame all around the front which is entirely grille. A lot of heat (unwanted) comes out of this. 
Has anyone blocked this off and relied on loosing the waste heat out of the exterior vent by fan or deflection? 

Mark.


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## pippin (Nov 15, 2007)

I made a fan unit for the roof window over our bed area.

I used two 120mm computer fans.

By use of a DPCO switch I can operate them at full speed or at half speed by putting them in series.

They blast out (well in actually) quite a lot of air at full speed but are noisy. 
That is the setting we use during the day when we are not in the van.

On the half speed setting they are virtually silent and give just enough breeze for night-time use.

I tried a 60mm fan for the fridge unit but it is really noisy.

I am going to get two 80mm fans and wire them in series.
That way they will run nice and quietly.
The other advantage is that two fans (or even two pairs) will cover the vent area more effectively.
Remember also that two fans in series take half the current of just one fan.

Watch this space!


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## Autoquest (May 16, 2007)

I have just bought a 'Vento' kit which looks OK - although I will have to attach it the back of the grill as the gas pipe get in the way otherwise. Can I ask how you all got a 12v supply into the back of your fridge? I don't want to drill holes through the metal (ish) containment box but at the moment I can't see another way.


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## TDG (May 26, 2009)

krull said:


> I have the usual Electrolux 3 way ...
> This year I made myself a cooling system:
> Electronic thermosat kit from Maplins £5 (you have to solder it together).
> 120mm computer cooling fan from Maplins £6
> ...


I was going to see see if there was a way to control the fan using the fridge's thermostat circuit but haven't had time yet to explore that one.


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## oldun (Nov 10, 2005)

Texas said:


> My fridge is boxed in (as per John Wickershams' advice) from the rest of the van and it has a deflector to guide the hot air out of the top vent, we've also had 2 quiet running fans fitted to our top vent for the last 4 years.
> 
> They have built-in gizmos that allow the fans to run faster as the air over them gets hotter, If the air is cool they don't run. They cost £3.49 off ebay at the time. I have wired them to the leisure battery via a switch so that they can be switched off at night, or, when required.
> 
> They are superb at extracting the hot air - 'tho you have to go outside to check that they are in fact running, they are so quiet - especially down at the Med.


Why are they quiet only down at the med?


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## lgbzone (Oct 8, 2008)

krull said:


> I have the usual Electrolux 3 way fridge, When used for extended periods, no matter what the power source, it appears to lose interest after a few days, and doesn't cool like it should. The cooling unit was replaced last year under warranty, but didn't make a huge improvement.
> 
> This year I made myself a cooling system:
> 
> ...


Hi Krull

if i can offer some advice about computer fans

a standard 120mm fan will be quieter than a standard 80mm fan and move more air, have a higher CFM rating which is cubic feet per minute of air they can move, 120 fans are quieter because they spin slower whilst moving the same or more air. a quiet 80mm fan may be a little bit quieter than a standard 120 fan but will have a drastically reduced CFM rating, i think your best bet would be to get a quiet 120 mm fan so that you can reduce the noise but keep the higher cfm rating.

cheap quiet fans are a rip off because they generally have the lower sound by simply spinning slower, this obviously means they have a lower cfm rating, quality quiet fans have advanced blade design and/or better bearing designs which means they are quieter without sacrificing the air flow.

the best computer fans for air flow against noise are made by silenx, they use fluid bearings and last for years, this company specialises in low noise computer parts, however they are more expensive than most.

a couple of good places for quality pc fans are www.quietpc.com, www.custompc.co.uk and www.specialtech.co.uk, there are many more places. if you check out pc shops such as i have listed here you will find that they always state the air flow in cfm, the noise level in dba, the power they use and the rpm of the fan, much better having this info prior to purchasing.

pc shops also sell many assesories for fans such inline resistors to slow them down, reducing noise and air flow. also rubber type gaskets that dampen vibration and reduce noise, there are rheostats available so you can fine tune the exact rpm/cfm and noise of the fans using a small knob.

a fan at around 22dba inside a computer case will not be heard in a room, fans are available as low as 11dba but the cfm is lower. it's better to have several slow fans than less faster fans, from a sound point of view, i can't remember the exact formula but it is something like; if a fan runs at 25dba, adding a second exact same fan only increases the noise by about 3dbs, where as using a single faster fan to move the same amount of air as the two increases the noise a lot more.

just in case it's useful; practically all pc fans have two small arrows on their edge which state the direction of the blades and the direction of the air flow, normally you need to position the fan just in the right light to see them. also the dba scale isn't linear, i think an increase of 10dba actually doubles the sound, so a 30dba fan is twice as load as a 20dba fan.

i probably sound like a right anorak posting this but i'm a systems engineer which can't stand noisey systems.

could be worth googling around to see what is available before buying a fan from maplins.

cheers
Lee


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## TDG (May 26, 2009)

I'm really quite surprised that these absorption fridges work as relatively well as they do in our MHs.
They rely on the temperature differential of the ammonia between the top and the bottom of the condenser tubes and the slope of the tubes to make the circuit operate correctly
Therefore, if the heat is not being taken away from the tubes sufficiently and the tubes are not at the optimum slope because the vehicle is not level, the fridge will never perform as designed. 
So, any additional ventilation that can take the heat away has got to be good and the fridge also gives another reason to keep the vehicle level.
Finally on ventilation, always suck - never blow! 
Finally finally this type of fridge can never be as efficient as the compressor type.


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## camper69 (Aug 30, 2007)

Has anyone improved the performance of the fridge on 12v by using the fans one the move?

My fridge/freezer struggled to cope in Italy last week when we were travelling for more tham a couple of hours?

Derek


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## Autoquest (May 16, 2007)

I hooked my fans up to a live feed from the leisure battery so as to be able to use them in auto whilst on the move - The performance of the fridge is much better.


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