My new to me fridge is cooling unevenly, but in odd ways....

[urbex]

Recently picked up a Norcold Tek II MFRT-360D, which near as I can tell is virtually identical to the Engel MT60. This is my first portable compressor fridge, so I don't really know what to expect or having anything to compare it to. Picked it up Monday evening, plugged it into AC, turned the dial approx halfway and forgetting how these fridges work...kept turning it colder every time the compressor would shut off, eventually ending up one number warmer than max cold (yep...forgot they need to go through a few cycles before getting really "cold").

I loaded up the far side with 15 water bottles, essentially filling the basket with standing 20oz bottles, but not packing them in. The near side (next to the compressor) I put in 3 bottles of beer, and my remote temp sensor in the bottom. Checked on it yesterday evening, and a few of the water bottles were turning into slush, and everything else felt cold. Temp sensor said 20*F.

Checked on it again this morning before I went to work, and found several water bottles in the middle of the pack frozen nearly solid, but most of them on the outer edges of the basket being cold, but not frozen at all. Now, I don't expect these things to work just like my home fridge, but this also seems a bit odd that the ones in the middle would freeze first. Is that just normal for these things? I'm thinking I may add a computer fan or two as circulation fans inside.

 

[teotwaki]

is that supposed to be a MRFT-60D???

 

[1MK]

Been having a similar "issue" with my Waeco. You can place a temperature probe in different areas and get radically different results. It has to be from the lack of circulating air.

I've spent the last couple days researching the idea of placing a small fan and pipe for circulation in a corner to help out. I'll lose a bit of storage space, but I think the cooling efficiency will be worth the trade off.

These are the only two other discussions I've found that had pictures for ideas:

http://www.expeditionportal.com/forum/threads/7268-Two-Zone-Club (towards the end)

http://sharkcaver.blogspot.com/2012/03/fridge-fan-mod.html

 

[teotwaki]

Been having a similar "issue" with my Waeco. You can place a temperature probe in different areas and get radically different results. It has to be from the lack of circulating air.

I've spent the last couple days researching the idea of placing a small fan and pipe for circulation in a corner to help out. I'll lose a bit of storage space, but I think the cooling efficiency will be worth the trade off.

These are the only two other discussions I've found that had pictures for ideas:

http://www.expeditionportal.com/forum/threads/7268-Two-Zone-Club (towards the end)

http://sharkcaver.blogspot.com/2012/03/fridge-fan-mod.html

In the Expo thread the fan I built on page 4 is still working well at distributing the air. I like the fan in the blogspot article. That one has a nice form factor.

 

[urbex]

is that supposed to be a MRFT-60D???

Nope. Says Norcold Tek II on the lid handle, and the data tag sticker says MFRT-360D. I just assumed it was a Norcold number difference.

http://www.thetford.com/HOME/PARTS/NorcoldIncRefrigerators/MRFT360Series/tabid/508/Default.aspx

Seems like this isn't exactly an uncommon issue with these types of refrigerators, and I expected some level of uneven cooling as they don't have fan circulation, I was just surprised as how uneven it was...I expected the bottles closest to the edges to be freezing first, not the other way around. I was thinking about just zip-tying a couple computer pancake style fans to the baskets, say one in the upper right corner blowing to the left, and one in the lower right corner blowing to the right, thinking it would cause the air inside to continually circulate in a counter-clockwise motion. Perhaps adding a relay to be triggered by the thermostat as well on a simple delay timer.

 

[1MK]

Here's my first prototype ducting I made out of styrene. I'll have it wired up tonight to test how well it works.

I think the slight loss of space will be worth it as we restock adult beverages quite a bit and improved cooling would be welcomed.









Ordered a couple different size blower fans as well to try and see if I can reduce the size, and try to get those mocked up sometime this weekend.

 

[teotwaki]

Really nice duct for the fan!!

 

[4x4junkie]

That's some nice work for sure

Yeah, you want a small size, lowest-current fan you can find (less than 0.05A or 2CFM, if you can find one). It doesn't need much air current to keep the air circulated (and the heat generated by a more-powerful fan motor will cause the fridge to work harder). A dropping resistor (outside the fridge compartment) can help too.

 

[highdesertranger]

I have 2 engels mr040f's and like the pic that teowaki posted, the condenser goes all the way around the box. there are no warm or cold spots. highdesertranger

 

[1MK]

Wanted to give a follow up on the recirulation fan setup. I ended up changing it to a blower fan to save some space and increase the air volume. While, I don't have any fancy monitoring results or temp probe readings every 30 minutes, I have noticed a significant difference in how long it takes newly introduced items placed in the fridge to cool down.

Drinks used to take for what seemed like forever to cool down, now are frosty cold in about 1.5 hours. The readings I have taken with a thermometer are now consistent throughout the compartment.

So far, very happy.

 

[Scoutn79]

The difference between frozen water and liquid water is 1deg F. Unless you can measure the water temp of each bottle separately I am not sure you have a problem. Your issue sounds to be the exact opposite of what I would think would happen.
The only thing I could think of is the outer bottles are closest to the walls and thus closer to the warmer air outside and the outer bottles are insulating the inner ones. Either way once the air and items temp stabilize you should be fine.
Personally I don' think a recirculating fan is needed in such a small space. Keep an eye on when things freeze as you use it and keep it just above that setting. Your house fridge only needs to be set to just below 40deg F so you shouldn't need to worry about keeping the temp above freezing.

Darrell