Maybe this will keep my fridge cool?

[mike4947]

Frost on the cooling plate will be familiar to anyone old enough to remember before there were frost free home fridges. Just opening and closing the door would/will cause moisture laden air to enter and the plate is a nice icy cold surface for that mositure to condense on and freeze.
I can remember as a kid my mother spending hours with pots of boiling hot water in the freezer trying to loosen up the ice/frost that would build up....mainly from me standing there with the door open staring at the food figuring out what I wanted....LOL

[austinado16]

That is because all of the coils you mention are not exposed to sunlight.  Black absorbs heat.  Being black does not make it radiate heat any better than being white, grey, blue or purple.  Being black makes all of your examples merely LOOK better than a colored device.

Thus, if your new fridge coils never see daylight, then black will not help them, and they will look "cool".

But, if your coils see daylight, you want them to be as non-absorbing as possible - so, silver or white.

Sorry zamboni, but that's not correct.  All sorts of mechanical devices are painted black for heat disappation and few if any of them ever see the sun.  Refer to my list, and then look around you in the real world.  In this scenario, we're talking about metal that's hotter than it's exterior surroundings on one side, and painted black on the other side to promote heat transfer.

Yes Mike, I'm familiar with those refrigerators.  I've restored a 1952 Philco Advance Design and it's been in use full time as our only refrigerartor for 14 years (gloss black painted condensor coils on the back and gloss black painted compressor underneath, just as the factory built it.)  I defrost it about every 3-4months.  

Fridge performance testing update: 7:45am and a huge thunderstorm has been raging since about midnight with rain off and on and a low of 37*F on my digital thermometer!  63*F outside right now and the fridge is 34*F inside.  Also, no leaks in the newly rebuilt roof or canvas.

[austinado16]

1:30pm 87*F outside and 41.5*F in the fridge.

[AustinBoston]

1:30pm 87*F outside and 41.5*F in the fridge.

Which most people would find unacceptable.  The "danger zone" for uncooked food is between 40

[austinado16]

Which most people would find unacceptable.  The "danger zone" for uncooked food is between 40

[mike4947]

Check out this website: http://www.rvmobile.com/Tech/Trouble/vent.htm
scroll down the page to "almost good venting".
It shows how a PU fridge should be vented and baffled.
We found over 1/2 the fridges we've looked at over the years to be installed incorrectly according to the fridge makers installation instructions.
Missing or inadaquate baffling is the main problem. Improper placement of the upper vent that allows hot air to pool at the top of the fridge compartment (we've seen it bad enough to blister counter top material). Door seal is another cause check it around the perimeter using a dollar bill, and damaged or missing insulation around the box a distant fourth.

[austinado16]

Thanks Mike,
Yes, that's an excellent website.  I actually called and talked to "T.J." who owns it.  Super nice guy and very knowledgeable.

After seeing that page on his site about 2 months ago (before our first trip) I added the lower baffle like you see on his page there at the bottom.  The fridge already had the nicer "ramped" baffle at the top that goes out to contact the condensor fins.  It even has a baffle at the very top so hot air has no choice but to go out.....it's a big sheetmetal flashing.

To all this I added the reflectix and filled in the space between the lower and upper baffles with reflectix so it would be less of a pocket.  The fridge body insulation is perfect and the door seal seems to be good all the way around.

I guess it's just time to add the little 12v fan and be done with it.  Or step up and replace the fridge (and that's not happening).

[mykwalker1]

Agreed. During the afternoon "heat soak" it's now up to 46.9*F with an outside temp in the mid 80's.

I know I've got a good flame and clear chimney, etc. so the only thing I can think of, is that just like a car's A/C system, this fridge is low on refrigerant and at higher outside air temps it just can't tranfer enough heat.  Bummer.

How much food/product do you have in the fridge?  An empty fridge works very harder to maintain temperatures than a full/stocked fridge.  

Try putting in a bunch of water bottles/soda or the like then check the temperatures again tomorrow.

Good Luck.

[mike4947]

Well I can pretty much assure you it's not "low refridgerant".  You'd notice a yellow pollen like substance (a chrome addative) around the back of the fridge and a definite ammonia smell.
Both Dometic and Norcold recommend mounting any suplimential fan so it blows out the upper vent.
And don't forget to check out the entire perimeter of the door seal. Only a couple of inches of "gap" where you don't get resistance from a dollar bill (we use them as they are really good quality heavy tear resistant paper) can have a fridge temp up 10 or more degrees.

[austinado16]

Well I can pretty much assure you it's not "low refridgerant".  You'd notice a yellow pollen like substance (a chrome addative) around the back of the fridge and a definite ammonia smell.
Both Dometic and Norcold recommend mounting any suplimential fan so it blows out the upper vent.
And don't forget to check out the entire perimeter of the door seal. Only a couple of inches of "gap" where you don't get resistance from a dollar bill (we use them as they are really good quality heavy tear resistant paper) can have a fridge temp up 10 or more degrees.

Okay, just checked it with a bill.  The seal is tight all the way around.  I've had the temp dial set to "max" since about 4 today and right now the fridge is at 28.4*F......not that it really matters because it's still getting into the hight 40's during the afternoon heat.

There's definately no yellow staining or ammonia smell.  Maybe it's damaged internally from age (it is 20 years old) or from being operated when not level.

Time to quit talking about it and mount that fan, as you suggest.  I appreciate your input! Oh, and here's how I baffled the bottom air intake...

[austinado16]

Here's how the 2 upper bafflers were installed by Starcraft.  The upper horizontal one fits right on top of the fridge.  The angled white one rests about in the middle of the condensor fins so all air has to go through the fins before hitting the horizontal baffle and going outside...

[AustinBoston]

Here's how the 2 upper bafflers were installed by Starcraft.  The upper horizontal one fits right on top of the fridge.  The angled white one rests about in the middle of the condensor fins so all air has to go through the fins before hitting the horizontal baffle and going outside...

The lower baffle looks fine, but on the upper baffle, there is a gap (on the right in the picture) of about 3/4" that would allow warm air to escape into the space between your reflectix and the fridge.  Surrounding the firdge with warm air (and then effectively insulating that compartment to keep the heat in when you menat to keep the heat out) may be a contributing factor.

Also, knowing it is a 20 year olf fridge makes me feel better; I was really thinking "he should be getting much better performance than that," but that was when I though you had a relatively new fridge.

Austin

[austinado16]

Okay, day 3:

Fridge is has cold food in it as of about 8:30am......thanks for that suggestion, I was wondering if the temp swings would level out some if there was stuff inside acting as a cold storage.

Pulled the upper louver panel off and an laid in a "baffle" of Reflectix against that metal upper baffle. Cut the Reflectix to span the full width of the wood framed opening, so there is no longer a gap (to the right in the photo) or to the left (which was there because of how the chimney comes up in that corner).  So that should take car of improving the passive convective air flow.

Heading over to Radioshack right now to pick up a fan.  Inside of fridge is sitting at 35.5*F right now with an outside temp of 70*F.

One thing I have noticed is how sensative the system is to having the louvered panel and louvered door off.  It actually came up in temp while I was working on it with the panels removed.  With them back in place, and while typing this, it's come down a point.

[mykwalker1]

Okay, day 3:

Fridge is has cold food in it as of about 8:30am......thanks for that suggestion, I was wondering if the temp swings would level out some if there was stuff inside acting as a cold storage.

Pulled the upper louver panel off and an laid in a "baffle" of Reflectix against that metal upper baffle. Cut the Reflectix to span the full width of the wood framed opening, so there is no longer a gap (to the right in the photo) or to the left (which was there because of how the chimney comes up in that corner).  So that should take car of improving the passive convective air flow.

Heading over to Radioshack right now to pick up a fan.  Inside of fridge is sitting at 35.5*F right now with an outside temp of 70*F.

One thing I have noticed is how sensative the system is to having the louvered panel and louvered door off.  It actually came up in temp while I was working on it with the panels removed.  With them back in place, and while typing this, it's come down a point.

You may want to hold off on the fan ... you'll be surprised how much the addition of food will make a difference.  Any heating/cooling device works a lot better when there is already product in unit.  Without product ... it has nothing to cool but itself and nothing to hold that cold air making it always working.

Let us know what that does (the addition of food) to the temperatures.  I think that you'll find it maintains a lot better temps.

[austinado16]

You may want to hold off on the fan ... you'll be surprised how much the addition of food will make a difference.  Any heating/cooling device works a lot better when there is already product in unit.  Without product ... it has nothing to cool but itself and nothing to hold that cold air making it always working.

Let us know what that does (the addition of food) to the temperatures.  I think that you'll find it maintains a lot better temps.

You are correct sir!  

87*F outside and the fridge temp was in the mid 36's before pulled the louvered panels off and installed a little 1-9/16"x1-9/16" 12v computer fan from Radioshack.  I decided to install the fan regardless of what the fridge temps did today because I wanted the option of additional cool if needed.

Fridge got up to 38.7*F during the installation of the fan.  During the time it took to snap a couple photos and right this, the fan has dropped the fridge temp to 38.3*F.

Fan is part number: 273-240
6,500rpm
.13amp (130mA) of current draw
1.56watts max
7.7CFM (cubic feet per minute) air flow
29dB noise level (can't hear it unless my head is right next to the louvers)

I installed the fan at the very top of the opening right up front next to the louvers, and centered on right grill opening which is where the majority of the heat lives and exits due to the chimney being there.  As you can see, I ran 2 galvanized sheetrock screws in along each side of the fan and then ziptied the fan housing to the screws using the 4 holes in the fan housing.  Fast and simple.

The switch is in the upper left corner of the lower opening, and wired in to break the ground circuit.  Radioshack part number: 275-730 and came with it's own mounting surround that screwed right into the upper wood crossmember.  Again, fast and easy.  Wiring is as you'll see in the next photo.