External fridge fans

[poppycamper]

Hi all
I know this subject has been covered before... but my query is not how effective they are but the positioning of the fans
I had a twin set up in the top of my caravan fridge sensing the air temp and extracting hot air straight out top vent which worked very well....
However I notice that the proprietary Dometic or Truma ones are fitted lower down the back of fridge and blows the air up thru the condenser and has a sensor directly on pipework and therefore sensing refrigerant as opposed to air temp.
Do any of you have experience off both setups and if so would you consider the second setup any better or are they both pretty much same same.
Thnx

 

[DBK]

Hi all
I know this subject has been covered before... but my query is not how effective they are but the positioning of the fans
I had a twin set up in the top of my caravan fridge sensing the air temp and extracting hot air straight out top vent which worked very well....
However I notice that the proprietary Dometic or Truma ones are fitted lower down the back of fridge and blows the air up thru the condenser and has a sensor directly on pipework and therefore sensing refrigerant as opposed to air temp.
Do any of you have experience off both setups and if so would you consider the second setup any better or are they both pretty much same same.
Thnx

A sensor on the refrigerant would be better, which I guess this is why they use this method,. It will also be easier to design a universal kit which doesn't have to interface with the MH as installations vary so much.

But the bottom line will be if the fans are moving air over the condenser they will work, whether sucked or blown.

 

[poppycamper]

Thanx DBK.. yea I was thinking more of sensor positioning as apossed to fan position.

 

[Camdoon]

I fitted 3 fans on the top vent at the start of CV19 and have a switch inside the van for off/on. You cannot hear or feel the fans so I will have to think about how to know if the fans are being powered.
To test, the van was sitting in the direct sunlight last week with temperatures over 30 (normally would be shaded by awning) and the fridge was as cold as required over 3 days (glass of water left in fridge and checked circa 1700hr). Quite happy to switch the fans on full-time when I cross the Loire.

 

[Gellyneck]

...... You cannot hear or feel the fans so I will have to think about how to know if the fans are being powered........

Swap your switch for one with a tell-tale light on it?

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[Lenny HB]

Computer type fans are more efficient extracting air rather than blowing. I fit my fans to the top grill with the sensor mounted on a strip of aluminium between the fans. The Domectic ones are not that good and very expensive for what they are, a couple of fans mounted on the top grill with a temperature controller works far better. With a temperature controller you can set it up for your individual fridge installation I set mine so the fans come on when the ambient temperature is 25 deg, in my case to do this the controller is set to 32 deg (last van it was 35 deg for the same result).

 

[Off da Grid]

I fixed a 120mm computer fan to the top vent , I didn’t bother with a temp sensor just a switch in the cupboard above the fridge.
Works really well

 

[poppycamper]

Thanx for replies... looks like a fan or two or three in top vent then. As stated originally that is set up I had in last c'van.
Just found it strange that Dometic fit a single fan where they do.

 

[Richard n Ann]

You don't want too much extraction, the absorption fridges use heat to drive the system. In compressor systems it's called 'over condensing' and some systems drop the condenser fan out periodically in the winter, to keep the head pressure up.

My sensor is stuck in the condenser fins, it's more efficient to measure refrigerant temperature and the fans will switch off when not needed.

 

[Petehvan]

I fitted 2 fans to the upper vent to extract warm air, I also fitted 1 fan drawing air in through the bottom vent these are attached to a temp. Controlled switch inside the van, this has a sensor sited in the back of the fridge. The setup works a treat and thanks to eBay the total cost of the job was under £20.00

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[MitchandJenny]

I got a thermostatic temperature box from China. Adjustable setting for cut and cut out temp on a digital display and a reading showing present temp.
Box measured 3 inches by 3 inches and 1 inch deep. I put it into a Tupperware type box and wired it via a small rocker switch fed from a fridge feed inside the outside van access panels.
2 computer fans mounted in top vent blowing out.
Worked trouble free for 6 year
That was before these fan kits were around.
Worked in 32 degree Greek weather.
Mitch.

 

[MitchandJenny]

PS that was cut in and cut out.

 

[Richard n Ann]

These are the most simple (and cheap) thermostats you can buy. They will switch 1.5 amps and don't use any power...

https://rover.ebay.com/rover/1/710-...0001&campid=5338547443&icep_item=263427334438

 

[PeteH]

Had 2, scavenged from a couple of scrapped computers, in the Winnebago, rigged in the top under the vent roof cover. Switched manually. Helped with Temperatures of 100+F in a Texan Summer. As we ran for cooler climes! in Colorado.

 

[Northernraider]

can a few folk show a photo of your diy fan installs as I'm looking to fit a couple on mine. Don't think I'll bother with a temp gauge just an illuminated on off switch.

But a pic of how fitted would be handy ...my hymer has the larger upper fridge vent

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[Newfie]

I have one of these comes with mounting brackets pick up 12v feed from back of the fridge & a drill a small hole to mount control panel somewhere close to fridge
Amazon product ASIN B07HHRNYF2

 

[Richard n Ann]

If you don't fit them on the louvre you can remove it for even more ventilation (if thermostatically controlled they will run less)

 

[Richard n Ann]

Oh another tip is to wire the 2 fans in series to make them run slower and quieter

 

[pelican]

View attachment 405552

If you don't fit them on the louvre you can remove it for even more ventilation (if thermostatically controlled they will run less)

Please could you tell me where I can purchase these

 

[pelican]

Please could you tell me where I can purchase these

ah just ordered from ebay!

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[NorthernSands]

I have two, slim Akasa fans to fit (had to be slim as there's not a lot of space between the fins and the vent) along with a temperature controlled switch and a temperature based PWM fan controller. In theory it should be fit and forget. There's a 12v feed and a broken fan already there. There's a dedicated switch on the fridge panel.

 

[Brockley]

These are the most simple (and cheap) thermostats you can buy. They will switch 1.5 amps and don't use any power...

https://rover.ebay.com/rover/1/710-...0001&campid=5338547443&icep_item=263427334438

Looks like a good way to control things and a good set up, but having little electrical experience could you explain a little more about how everything is wired up and how it works please

 

[Richard n Ann]

Go for the "Normal open" 45°c version.

Extremely simple to wire up. Take a positive 12v supply from somewhere, run it through a fuse and on/off switch if you want, then connect it to one of the component pins (doesn't matter which) then from the other pin to the fan positive wire, then wire fan negative to chassis ground.

Stick or bolt the component onto the last condenser fin on the left ie the cool end.

Mine fans are on an electronic thermostat I made, but I have used these mini thermostat things before and they work spot on.