Electrical Fridge Fan
- Thread starter brookes2622
- Start date
Yeah do tell!
Thanks to this thread you guys have me thinking about installing one too.... Grrr
Looking at the store bought jobs, their cost etc, I really think I could make some pocket money making up a kit.
If you make your own, the thing you have got to look out for is mount the fans so they are pulling the air thru the fins, position them so if one fails you can remove it easily by a couple of screws and unplug the cable not have to dismantle the whole shebang like some I have seen.
I wouldn't close off the exhaust vent to force the fans to pull the air, if you loose the fans or power to them you won't even have normal convection air flow and may not know it till you food is hot and the fans would have to run all the time.
I like the zip tie to the vent idea, easy access to the bits.
Remember KISS, it works every time........you can go all fancy with relays, switches and all the bells but think I could be sitting in the dirt out bush trying to sort this out.....KISS means, you pull the offending bit out of the loop, all is good and it takes 10 mins.
As for a fan inside, just looked inside mine and cannot see how it would be of use, theres no damn room for a flea.
If you make your own, the thing you have got to look out for is mount the fans so they are pulling the air thru the fins, position them so if one fails you can remove it easily by a couple of screws and unplug the cable not have to dismantle the whole shebang like some I have seen.
I wouldn't close off the exhaust vent to force the fans to pull the air, if you loose the fans or power to them you won't even have normal convection air flow and may not know it till you food is hot and the fans would have to run all the time.
I like the zip tie to the vent idea, easy access to the bits.
Remember KISS, it works every time........you can go all fancy with relays, switches and all the bells but think I could be sitting in the dirt out bush trying to sort this out.....KISS means, you pull the offending bit out of the loop, all is good and it takes 10 mins.
As for a fan inside, just looked inside mine and cannot see how it would be of use, theres no damn room for a flea.
I'm with you @bigcol the simplest seems to the zip tie method. Easy acces to a panel that is designed to be removable, and the normal convection will still work.
I also put in foam between the fins and the wall and around the side to make sure all the air went through thoses top fins and down the side between the tubes and the boiler to stop that heat from being pulled up through the fins from that aswell. Made a huge difference knob sat between 2 and 3 depending on the heat of the day and day or night. (this is why i went the waeco 12v in the new van set it to 3 and forget about it)
If you dont close of the vent you will be just pulling in air back through the top vent, the fans dont know they have to pull air up through the fins they will just pull in air from the path of least resistant. This is why every vehicle has a engine fan shroud to force the air through the radiator and not just pull it from the sides, and why when they are damaged or removed the engine overheats.
and dont worrie drover there is still heaps of room for the fridge to breath when the fans are not going, you are only relying on warm air rising so there is not that much pressure behind it.
If you dont close of the vent you will be just pulling in air back through the top vent, the fans dont know they have to pull air up through the fins they will just pull in air from the path of least resistant. This is why every vehicle has a engine fan shroud to force the air through the radiator and not just pull it from the sides, and why when they are damaged or removed the engine overheats.
and dont worrie drover there is still heaps of room for the fridge to breath when the fans are not going, you are only relying on warm air rising so there is not that much pressure behind it.
@ShaneT I like the extra baffles and the theory behind the fans position, I did an air flow test with mine, mossie coils for smoke and found that they drew the smoke from the lower vents and none from the upper surrounds, I do have 2 fans fitted and they cover most of the vent anyway. I think I did think about foam on the edges but those pipes get that hot thought I'd leave it to mod 2 but haven't needed one.
Be nice to pull the fridge out and build a nice air flow baffle.
Be nice to pull the fridge out and build a nice air flow baffle.
Yes, Ive no doubt it makes a big difference when the air temp creeps up outside. I only had a small computer fan cable tied to the upper vent and that made a noticable difference.
I didnt suddenly become a compressor fridge ... but it gave it a little leg up on the those really hot days.
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Just picked this up at Jaycar for $20, should help keep an eye on the fridge temps as compared to ambient.
I may even get motivated and do some trials with fan and without.
Im hoping it will transmit from the fridge to the car so i can keep an eye on things while on the move using the crappy 12v feed.View attachment 30476
This was the reading this morning with the fridge on 240v overnight, setting 5.
I may even get motivated and do some trials with fan and without.
Im hoping it will transmit from the fridge to the car so i can keep an eye on things while on the move using the crappy 12v feed.View attachment 30476
This was the reading this morning with the fridge on 240v overnight, setting 5.
No it doesn't need to be more efficient, but you could say that about the fans as well, 99.9% of the fridges out there don't have a fan and do ok. Like most mods on this forum, there more of a want to do thing rather than a need to.
Got all my bits together to do mine. Interesting Jayco left a metre of 12v cable just at the back of the fridge unterminated! It comes of the bunk light. Talking with a Thetford rep he said there fridge are going to start shipping with fans. I wonder if this was what it was left for?
Bits all waiting.
Bits all waiting.
The fridge evaoprator heats the air behind the top vent. That hot air naturally convects out through the top vent as the air is heated. This in turn causes a low pressure lower down behind the fridge and that lower pressure draws in the outside air through the lower vent which is generally cooler; keeping a continual flow of air over the fins and bleeding off the heat built up in the cooling fins
When the outside temp raises, the efficiency of the convection process slows down as the temperature at bottom vent raises closer to the temperature already at the top vent. If the temperature outside gets high enough, the pressure at the bottom vent will raise to match the pressure at the top vent. If this happens the convention will slow down, and can stop all together producing a air lock. If the outside temp is 40deg and the air temp at the top vent is around the same, the fridge internal temp will be on the rise to.
So whilst a fan probably doesn't do much most of the time, it will certainly increase the systems ability to function in really hot weather, and help to artificially keep the convention process flowing as that temp raises to avoid that airlock
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Okay so where to mount the thermostat? I went with a 50c but thinking now I should have gone 70c . Has anyone measured the top tube to know what temp it gets to and does it vary cause along its length as it would be easiest for me if I could mount it to the far left.
At 50c it will run all the time, mine is attached to a spring clip so it can be moved, replaced without problems and only by removing the vent. I fitted a 70c to mine and I did the temps and it was up around 70c + most of the time.
If this pic is taken from the upper vent opening then I would panel that open area in as the hot air will flow into that cavity and heat up a cupboard or bench top when you want it to go out the vent to improve the air flow.
From some I have seen the biggest problem with fridges is they are not installed as they are supposed to be. Just a read of the installation manual explains it all, if not installed properly then the fans are not going to work as well as they should and they really need it if they operate on 12v or 240v.
Feel the outside wall below the vent, it gets really hot so some temp is generated there, it will still be warm with the fan running on a hot day, so the fans do a good job.
Going over your post again @achjimmy I would fit your switch on a clip and sit it over the fins, will work just a swell with a 50c unit.
If this pic is taken from the upper vent opening then I would panel that open area in as the hot air will flow into that cavity and heat up a cupboard or bench top when you want it to go out the vent to improve the air flow.
From some I have seen the biggest problem with fridges is they are not installed as they are supposed to be. Just a read of the installation manual explains it all, if not installed properly then the fans are not going to work as well as they should and they really need it if they operate on 12v or 240v.
Feel the outside wall below the vent, it gets really hot so some temp is generated there, it will still be warm with the fan running on a hot day, so the fans do a good job.
Going over your post again @achjimmy I would fit your switch on a clip and sit it over the fins, will work just a swell with a 50c unit.
I spoke to a thetford service tech. He reckons that top tube starts on the right at about 120-130c and cools as it travels to the left. He reckons 50c will be okay about 50mm from the end? I like @Drover idea of the fins cause basically that's whats struggling to cool. I am waiting on a valve and I can get the gas going again and might take some Temps.
The install on the Dometic in the Expanda was better. Cause it sat lower but the vent was 250mm higher than the frigde and they made a curved panel to help the heat disapate out the vent.
The install on the Dometic in the Expanda was better. Cause it sat lower but the vent was 250mm higher than the frigde and they made a curved panel to help the heat disapate out the vent.
We have the full size, 2 door fridge. (Rm 4601 I think it is). I want to install one of those solar fridge fans. Is there any other way, other than taking the fridge out, of installing it?
FYI, this will not receive the signal while in the car. Bummer, but still a useful thing to have.
I'll mount it up next to the Solar regulator.
Saw a new thetford 2 door out the other day. Took this snap of the factory fan and switch
Apologies in advance for a very basic question on this thread but....how is the fan and thermo switched wired in? I'm assuming you locate a constant 12VDC source in the vicinity of the fridge, connect the switch in series with the fan and find a suitable ground. Should the fan be able to run whether fridge is running on 12V, 240V or gas? Thanks.