# thermostat control for fridge fan



## solly (May 1, 2005)

I had real problems with my fridge staying cold in Italy this year and having read al the posts on MHF I've now grought a decent computer fan to fit. what I cannot find is a recommendation for a suitable thermostat control with a switch (if appropiate) Could someone please advise me where to to get one.
Solly


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## TheNomad (Aug 12, 2013)

Others will no doubt be along in due course with better advice, but my first thought (having installed one of these fridge fans last year and been VERY VERY pleased with how it really helps keep the fridge/freezer down to temperature here in a hot region of Europe) is: why have a thermostatic control on the fan?

It so happens that I bought a ready-made kit from a motorhome accessories shop, so mine does have an adjustable thermostatic control. 
But the thing really does use utterly buggerall electric when operating, so if it was me I'd just fit a simple on/off switch in the positive feed from your leisure battery to the fan; maybe a switch with one of those tiny LED lights on it to show when it's running.
Then I'd run it all day whenever using the MH, and just switch it off at night.


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## kimbo4x4 (Jun 29, 2008)

If you search on a well known on line auction site for this:

Temperature Switch Thermostat 

You may find the kind of thing you are looking for. Maplins might do them - havent checked.
I have been thinking of fitting one too. Not sure if it is really needed as a simple on/off switch would do.


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## solly (May 1, 2005)

*refridegertor thermostat*

Thanks Nomad what you say makes sense to me unless someone comes up with better advice I think I will go this ruote.
Thanks also Kimbo. I did look on Maplins website, however I don't know what I'm looking for ie device make and model.
Solly


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## subfiver (Oct 15, 2011)

I used an old c.h. thermostat I had lying around. 

IMHO it's easier to fit a hidden thermostat than to route wiring to a convenient location for a switch. Thermostat, once set is 'fit and forget' you don't have to remember to turn it on and off !!


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## kimbo4x4 (Jun 29, 2008)

*Re: refridegertor thermostat*



solly said:


> however I don't know what I'm looking for ie device make and model.
> Solly


Foodstuff should be stored at 5C or below. So if you buy a switch that turns offon or below that it should do. There are plenty on EBay.


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## Ian_n_Suzy (Feb 15, 2009)

This is the Maplin one, it does come in kit format so needs soldering up. It's not a hard job by any means, and took me about 20 minutes taking my time.

http://www.maplin.co.uk/thermostat-...m5522X832722X11045e40b5d8957b62e453b71eea98b4


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## spykal (May 9, 2005)

Hi

There are some simple and cheap non electronic thermostats listed on amazon that would, I think, do the job ok.

like this one:

http://www.amazon.co.uk/Temperature...2EX20/ref=aag_m_pw_dp?ie=UTF8&m=A50DZI580G3JX

Mike


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## TheNomad (Aug 12, 2013)

*Re: refridegertor thermostat*



kimbo4x4 said:


> solly said:
> 
> 
> > however I don't know what I'm looking for ie device make and model.
> ...


No. The fan thermostat wouldn't, so far as I know, go actually INSIDE the fridge at all.

I've always understood such things to be fitted at the rear of the fridge, in the vent-space between the fridge and the outside wall of the van, near to the top of that ventspace....because it's that space that you want the fan to assist with sucking more air out of the top of.
So the thermostat cut in/out temp would be (I'm guessing here) maybe 30/40 degrees celsius.


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## listerdiesel (Aug 3, 2012)

Our little circulation fan runs 24/7 and without a thermostat. We leave the fridge on while outside the house as it keeps a bit of warm air circulating inside.

We also run it at half-power to keep the noise level right down.

Peter


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## spykal (May 9, 2005)

Hi again

I have often thought about adding a computer fan but no got around to doing it but having just found a suitable? thermostat on Amazon I then noticed these ...less that a quid each but you have to buy 5 :roll:

I have never tried to fit a fan but I am thinking that the fan will need to switch on only when the fridge is working flat out and one of these temperature switches could maybe be attached to the heat exchanger pipework of the fridge ...a little experimentation would be needed to get it positioned in exactly the right place so that it only tripped on when the fridge was working flat out and that part of the pipe work was above 50C .

http://www.amazon.co.uk/Celsius-Nor...F8&qid=1384859995&sr=1-14&keywords=thermostat

read the review ...it works ok with a computer fan :wink:

Mike


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## TheNomad (Aug 12, 2013)

spykal said:


> Hi again
> 
> I have often thought about adding a computer fan but no got around to doing it but having just found a suitable? thermostat on Amazon I then noticed these ...less that a quid each but you have to buy 5 :roll:
> 
> ...


I don't think it's the fridges pipework temperature that's at issue - that just carries the refrigerant gas around....I think it's the air temperature in the void behind the fridge, between the lower and upper fridge vents....the air around the heat-dissipation fins and gas flame exhaust stack.

You want the fan to be sucking that hot air upwards and away from those components and out of the top vent, thus drawing in cool air in from the bottom vent....and so the senser needs to be in that zone above the fins I think.


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## Mrplodd (Mar 4, 2008)

As has been said,

Why complicate matters in the first place??? I have a single (second hand) computer fan that is glued/screwed onto the inside of the top vent so it draws air over the cooling elements and exhausts it out of the vent.

It runs through a small illuminated switch located just above the sink that draws its power directly from the leisure batteries (so it still works if I go out and switch the habitation electrics off and leave the fridge on gas) 

It uses, as has been said, sod all power and is very effective. 

If its hot enough to need the fan in use it is highly UNLIKELY that it will ever need to be switched off anyway. 

It will run for about 50 years off 2 x 115 AH batteries so why bother with a thermostat? What are you hoping to acheive? Your Fridge is NEVER going to get THAT cold is it :roll:


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## listerdiesel (Aug 3, 2012)

TheNomad said:


> I don't think it's the fridges pipework temperature that's at issue - that just carries the refrigerant gas around....I think it's the air temperature in the void behind the fridge, between the lower and upper fridge vents....the air around the heat-dissipation fins and gas flame exhaust stack.
> 
> You want the fan to be sucking that hot air upwards and away from those components and out of the top vent, thus drawing in cool air in from the bottom vent....and so the senser needs to be in that zone above the fins I think.


Exactly.










Bear in mind that our particular arrangement is not standard, our chimney vents out of the side on the left, the view is from the engine compartment.

Peter


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## spykal (May 9, 2005)

TheNomad said:


> I don't think it's the fridges pipework temperature that's at issue - that just carries the refrigerant gas around....I think it's the air temperature in the void behind the fridge, between the lower and upper fridge vents....the air around the heat-dissipation fins and gas flame exhaust stack.


I agree, in part ..as it can be an issue if certain parts of the absorption system get too hot ( the condenser) ... the pipework at the top section of the system, where the ammonia gets condensed back to a liquid ( the condenser) is the part of the system that needs a good airflow over it to cool it ... what I was suggesting was siting that small thermostat onto the pipework at that part of the refrigerator absorption system where, when the system was working hardest, the pipework would be very hot ( too hot in fact) and the fan would then switch on.

You do have to keep in mind, in cooler ambient conditions, overcooling the rear of the fridge with too much airflow will just make the fridge heater work harder which will burn more gas .....quite a lot of heat is needed for the absorption system to work correctly. That is why winter covers are sometimes fitted. Getting the right amount of cooling at the back of the fridge is a balancing act :wink:

I had a go at trying to understand the absorption refrigeration process a while back :

http://www.motorhomefacts.com/ftopicp-1315347.html#1315347

I think someone else could maybe improve on that .... anyone :lol:

Mike


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## solly (May 1, 2005)

*thermastic control for fridge fan*

Spykal. The thermostat control looks ideal and fits in with what Subfive says about setting and leaving. Now I have to make my choice. Do I just have a switch or a thermostat ? both make sense.
As usual with MHF members you get a great response.
Thanks to everyone.
Solly


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