Fridge fans,where to put it.

Also whats the best way to get it in onto the fridge,take the vent out or take the fridge out, ive decided to get one of the solar ones tomorrow and give that a go over the christmas break while we are away.

In our previous van I installed the fan (3") horizontally about 1/2 way up the fridge. Made up a small al. bracket to mount the fan.
I also installed a sheet of poly foam about 9" deep by the full width of the fridge to create a better airflow. It was a full height louvre vent panel on the van wall.
Also sisal/foil to deflect the airflow back out the top of the vent.
The fan was switched on and off manually.
The improvement was immediately noticable, set on 2 stayed much colder and the gas bottle (9kg.) from 21 days to 26.
Our new van has had 2 x 3" fans mounted behind the top vent to blow hot air out. I connected via a thermostat on the top fins, switch on at 50deg., off at 40deg.
They certainly move some hot air!
The fridge works very well, but cannot compare before and after.
furph

Matt, you are not alone there would not be more than 5% of caravan fridges 3 way fridges that have been fitted in accordance with manuf specs. To do the job properly you must take the fridge out. At the back of the cupboard space where the back of the fridge finishes when it is in. you should fill in the gap all around the fridge so as to stop the hot air from the back of the fridge going around the sides of the fridge, this hot air gets traped around the sides and top and cant be moved causing the fridge to be working in much hotter environment than it should. Then you put the fan at the back of the fridge to circulate the air around the back of the fridge.Hot air rises ,so the hot air sits at the top of the fridge space so it is important to get the air flowing out the top vent,on most vans you will find that the vent does not go to the top of the fridge space sso you have a area of trapped air at the top,if so you are better to have a fan as close to the top as possible blowing out the top vent sucking out as much of that hot air as possible, another fan at the bottom faceing straight up helps pull the cold air in from outside and force it up over the condenser and also forcing the hot air up to the other fan,the two most important things are the flow of air and sealing oround the fridge so that air doesnt get trapped,its like wrapping a thick blanker around the fridge to keep it warm. Hope this is clear enough for you to get the idea of how it works, nothing is an exact science but if you can understand the fundamental workings you know how to the end result. Chris

Put it at the top so it acts as an extractor fan.

Many years ago I had a three way fridge and I fitted the fan directly onto the condensor. I also had it set up so that i could use the 240v thermostat when running on 12v. I then added a heap of insulation to the outside of the fridge and it did a pretty good job. Unfortunately i never had the facilities to determine the best location and effectiveness of any of the mods done.
I don't know if this will help but the article below details the results I obtained a few years ago with a compressor fridge and the location of the fan.
http://www.campertrailers.org/supercheap_fridge.htm
The significant finding was the placing of the fan to force cooler air onto the condensor rather than the extraction of the hot air. I don't know if this scales with regard to heat extraction from the area outside a fridge when located inside a camper.
To my mind the effectiveness of introducing cooler air directly onto the condensor as opposed to trying to suck the hot air away is similar to the effect you get standing near a fan. You feel more effect with the air blowing onto you than at the back of the fan.
It would be interesting to get another 3 way fridge and take some measurements to see what works best.

Matt,The gas fittings are flared fittings so you should not have any problems with putting them back together they are a dry seal joint,do not use any sealants when you have finished turn gas on and spray detergent and water mix over the joint , should not see any air bubbles. The plastic vents just have a coin slot to one side half a turn and the face comes off, not a lot of access through there . The idea of blowing cold air in is not the important issue it is circulation of air in and out , you must get rid of the hot air created at the back of the fridge, same principle as a radiator block off the air flow and it overheats, the hotter the environment the less efficient the 3 way fridge is. Chris