Refrigerator External Cooling Fan

[wavery]

Another possible risk with doing this (specifically blocking the upper chamber except where the fan is) is forcing too much air through the burner portion of the fridge.  I believe these are designed to absorb as much heat as possible as the heat from the flame slowly rises.  If you block the upper vent and put a fan on it, you will be sucking the hot exauhst fumes out at a point where you need things to be hot in order for the fridge to work.

It may also increas ethe risk that the propane flame will blow out.

Austin

Good point. All I was trying to demonstrate is that the fan would be far more effective in the upper chamber blowing to the outside.

I really don't feel that it is necessary to go to any extremes. Most people that I have seen use a fan have been very satisfied with this set-up.

I get a very good drafting effect with our fridge and haven't found it necessary to connect the fan(s) that I have. They're just laying in the bottom of my fridge compartment, quietly waiting for the day :p .

[wavery]

This was our setup on our 2002 Utah

http://kathybrj.tripod.com/id9.html

There was a significant difference in the cooling of the frige after the installation of this fan.

IMHO.....this is an ideal set-up.

[austinado16]

Thanks for all the feedback on this and for that link showing the fan installation.  That's how I've done it in my PUP, I just used too small of a fan....but I'm going to replace it with the big one like you have.

Wavery, I don't think you can compare the confines of the fridge's rear compartment to a bathroom in a home.  2 cubic ft. with a full width set of louvers at the top, doesn't compare to the airflow in a 2400 cubic ft bathroom with a 3" diameter fan in the ceiling somewhere.   Of course in the bathroom example a fan on the floor would do nothing.

But in our fridge rear compartments, it's all sealed and air will take that path of least resistance.......up the way it's pointed and then out the louvers at the top due to the pressure wave of air  you're creating just 12" below.

That being said, I do think mounting the fan up top is good, but I wouldn't go so far as to start blocking any louvered surface area off.  A 20-40cfm fan is a heck of a lot of airflow

[wavery]

Thanks for all the feedback on this and for that link showing the fan installation.  That's how I've done it in my PUP, I just used too small of a fan....but I'm going to replace it with the big one like you have.

Wavery, I don't think you can compare the confines of the fridge's rear compartment to a bathroom in a home.  2 cubic ft. with a full width set of louvers at the top, doesn't compare to the airflow in a 2400 cubic ft bathroom with a 3" diameter fan in the ceiling somewhere.   Of course in the bathroom example a fan on the floor would do nothing.

But in our fridge rear compartments, it's all sealed and air will take that path of least resistance.......up the way it's pointed and then out the louvers at the top due to the pressure wave of air  you're creating just 12" below.

That being said, I do think mounting the fan up top is good, but I wouldn't go so far as to start blocking any louvered surface area off.  A 20-40cfm fan is a heck of a lot of airflow

I was merely using the bathroom example as an illustration of the concept.

The louvered panels (upper & lower) work well for drafting. However, when you add a fan in the mix, you loose all of your drafting effect. Admittedly, some of the air will escape through the upper vent IF air is encouraged to enter the lower vent (as in drafting). The way that they have the fan placed in their illustration, I see no reason that the air that is forced through the fan would necessarily come in through the lower vent. I think that it is just as likely that the air supply could come from anywhere inside the cabinet and may well just be recirculated hot air (speaking of which....I'm burned out on this topic ). There is NO positive pressure on the intake that would force the air out of the upper louvers.

I just don't think that their design is well thought out.

[austinado16]

...speaking of which....I'm burned out on this topic )...

Sorry man, didn't mean to burn you out.  

I was just asking because I thought this might make a good learning experience and a good thread for the archives since fridge issues are discussed fairly often here.

[wavery]

Sorry man, didn't mean to burn you out.  

I was just asking because I thought this might make a good learning experience and a good thread for the archives since fridge issues are discussed fairly often here.

I was just kidding......it just sorta fit in my post :sombraro:

Heat....burned out......get it?? hahahahaha :morning:

[mike4947]

Note that both Norcold and Dometic have fan kits and both recommend installing them in the upper vent on units installed in RV's that do not have a roof stack ventilator.
But as I've said many times, your average PU fridge if correctly installed and maintained will keep safe temperatures well into the 90 degrees F wihout a fan.

[austinado16]

Just got off the phone with "Elaine" at Dometic.  Elaine said these little refrigerators are only tested for cooling up to 90*F outside air tempurature and after that, they really begin to struggle.

She sent me a 2 page pdf of how they want their refrigerators installed, and it includes the installation of the external fan that they use.

To cut to the chase, they are using a 95-100cfm computer style case fan that uses 7watts (.59ams).  On some fridge installations they mount it centered in the upper louvers facing outward.  They're using a fuse in the 12v power feed and a temp sensor between the feed wire and the fan.  In other applications, they are turning the fan so it blows verticle upward though the condensor fins, mounting it right to the middle back of the fridge.

Looks like based on the amp draw vs. cfm, we'd be better off using 2 40cfm case fans at .11ea for a total draw of .22amps and nearly the same cfm.

Interesting stuff!

Here's the installation instructions..........

[wavery]

Note that both Norcold and Dometic have fan kits and both recommend installing them in the upper vent on units installed in RV's that do not have a roof stack ventilator.
But as I've said many times, your average PU fridge if correctly installed and maintained will keep safe temperatures well into the 90 degrees F wihout a fan.

That sure holds true on my fridge . That's why the fans that I have are still laying in the bottom of the compartment....."Awaiting the day".

[austinado16]

That sure holds true on my fridge . That's why the fans that I have are still laying in the bottom of the compartment....."Awaiting the day".

Well, it just keeps getting better.  After reading though the pdf info that "Elaine" sent me, I was still unsure about the fan installtion.  So I emailed her back and said which is the prefered; mounted behind the louvered panel, or mounted midway up the back of the fridge blowing up through the condensor fins.

Here's her repsonse.

"Hello Todd,

You are correct the refrigerator depth is almost exactly the same depth of the hole that the refrigerator is installed in.  In fact, our specifications for the refrigerator mandate that the cooling unit needs to be no more then 1 inch away from the external wall.  However, there is a space on the back of the refrigerator that the cooling unit does not touch and you can see the installation tape between the fins at the top of the refrigerator and the boiler assembly at the bottom of the refrigerator.  If you mount the fan, blowing upward, in this space it will give you around 4 or 5 inches to fit this fan in .  This location is the preferred place for the fan to be installed.  

In the picture below, you can tell it is a tight squeeze but between item 1 and 90 is were the fan should fit.  If for some reason it can not be installed there then it would need to be installed at the exhaust vent (or top vent) facing out.  Still creating a flow of air coming up from the bottom vent and blowing out through the top vent."

[mudrider420]

austinado16...is there a possibility that i can get a copy of that pdf. that "elaine" sent you??

[austinado16]

austinado16...is there a possibility that i can get a copy of that pdf. that "elaine" sent you??

Affirmative!

Just email me directly:  austinado16  at  cs    dot com

[austinado16]

Quick update:

Checked over at Best Buy today to see what their selection of computer fans was like.  They have a .11amp/34.5cfm 3" case fan with ball bearings for $10 and change. I bought it.  

That's $2 cheaper, moves 5 times the air, and at less amps, then the little 1-9/16" fan I installed from Radioshack during my fridge testing.

Needless to say, the new fan is going right in.