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Old 06-24-2015, 04:06 PM   #31
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My 4.3 cu. ft. (RM8551) Dometic fridge struggled to get below 40(F) all last summer. So last week I undertook a series of modifications that (with 4 days of use) seem to have made a significant positive difference in its ability to get into the (acceptable) low 30’s.

Using an Accurite thermometer with two sending units (one inside the trailer and one on the inside of the top half of the door), its best performance was a fridge temp of 34(F) with an ambient temperature of 84(F). Outside temperatures were a high of mid-80's throughout the 4 day trip. Getting to these acceptable numbers was the result of several modifications achieved over two days with the extensive support and encouragement of Tom (aka: “Kountry Kamper”) whose help was invaluable (if not essential).

The mods included the following:
• I replaced the original door with one recently provided by ETI which is said to have a denser foam insulation;
• I completely removed the freezer unit and left it at home;
• I removed the fridge and installed a new flue with R13 wall insulation using the design and materials recommend by Reace quite some time ago, posted on this forum. I also put an inch of foil-backed foam board on the sides as well as 3 inches of the R13 on the top of the fridge;
• I replaced the stock, flat plywood baffle with one angled at 45 degrees (on Tom’s tested recommendation). I used a scrap piece of lightweight vinyl sheet with Velcro to secure it to a piece of wood cut at 45 degrees attached to the flue frame;
• My unit had two stock factory fans (I’ve heard some have just one, and others possibly none) run in series to a thermal switch I have never heard run before. I simply cut the factory wires which I then ran to another power source and installed a rocker switch on the control panel on the fridge. During our trip, the fans ran 24/7 (a little noise, but not too bad). Bypassing the thermal switch means I’ve got to remember to run it without any backup;
• Lastly, I installed a “Snip the Tip” adjustable thermistor, replacing the stock unit. Surprisingly, adjusting the new thermistor made quite a difference in the fridge’s performance numbers (from 40 to 34). It is important to note that the gauge on the thermistor still had room for additional adjustment but 34 degrees was just fine. IMHO, this product really works very well!

This was not an easy modification. After unhooking the propane and electrical power, I had to use a 4 lb. hammer with a piece of 1x4 just to get the unit to wiggle a little (hit it on the bottom corners). I can not express how tight a fit it was. When I reinstalled, I removed a 1/16th inch wood shim on one side and it was still tight. Needless to say, there isn’t much room to work inside the fridge cavity and trying to get the back plywood flue panel installed in one piece is impossible. However, it can be ripped into two pieces that can be installed separately (with the insulation already attached using a spray adhesive). Once done however, it really seems to have improved the fridge’s performance. I declared victory when my wife complained that I froze some of the vegetables!

Ultimately, these fridges perform just like I do – great when it’s nice and cool or just warm, and struggle when it’s hot. I doubt that any one of these mods would have made such a difference, but rather it is the cumulative effect of all of them.
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Old 06-24-2015, 04:29 PM   #32
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Rich,
Great write up in explaining, any chance of pictures which may fill in between the lines?
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Old 06-24-2015, 04:34 PM   #33
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Originally Posted by cpaharley2008 View Post
Rich,
Great write up in explaining, any chance of pictures which may fill in between the lines?
I used Jon Vermile's posting of Reace's pictures and guide so nothing there. Only photo I have is of my two fans. Sorry ... But if anyone has any questions I'd be happy to help.
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Old 06-24-2015, 05:20 PM   #34
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Quote:
Originally Posted by Zardoz View Post
My 4.3 cu. ft. (RM8551) Dometic fridge struggled to get below 40(F) all last summer. So last week I undertook a series of modifications that (with 4 days of use) seem to have made a significant positive difference in its ability to get into the (acceptable) low 30’s.

Using an Accurite thermometer with two sending units (one inside the trailer and one on the inside of the top half of the door), its best performance was a fridge temp of 34(F) with an ambient temperature of 84(F). Outside temperatures were a high of mid-80's throughout the 4 day trip. Getting to these acceptable numbers was the result of several modifications achieved over two days with the extensive support and encouragement of Tom (aka: “Kountry Kamper”) whose help was invaluable (if not essential).

The mods included the following:
• I replaced the original door with one recently provided by ETI which is said to have a denser foam insulation;
• I completely removed the freezer unit and left it at home;
• I removed the fridge and installed a new flue with R13 wall insulation using the design and materials recommend by Reace quite some time ago, posted on this forum. I also put an inch of foil-backed foam board on the sides as well as 3 inches of the R13 on the top of the fridge;
• I replaced the stock, flat plywood baffle with one angled at 45 degrees (on Tom’s tested recommendation). I used a scrap piece of lightweight vinyl sheet with Velcro to secure it to a piece of wood cut at 45 degrees attached to the flue frame;
• My unit had two stock factory fans (I’ve heard some have just one, and others possibly none) run in series to a thermal switch I have never heard run before. I simply cut the factory wires which I then ran to another power source and installed a rocker switch on the control panel on the fridge. During our trip, the fans ran 24/7 (a little noise, but not too bad). Bypassing the thermal switch means I’ve got to remember to run it without any backup;
• Lastly, I installed a “Snip the Tip” adjustable thermistor, replacing the stock unit. Surprisingly, adjusting the new thermistor made quite a difference in the fridge’s performance numbers (from 40 to 34). It is important to note that the gauge on the thermistor still had room for additional adjustment but 34 degrees was just fine. IMHO, this product really works very well!

This was not an easy modification. After unhooking the propane and electrical power, I had to use a 4 lb. hammer with a piece of 1x4 just to get the unit to wiggle a little (hit it on the bottom corners). I can not express how tight a fit it was. When I reinstalled, I removed a 1/16th inch wood shim on one side and it was still tight. Needless to say, there isn’t much room to work inside the fridge cavity and trying to get the back plywood flue panel installed in one piece is impossible. However, it can be ripped into two pieces that can be installed separately (with the insulation already attached using a spray adhesive). Once done however, it really seems to have improved the fridge’s performance. I declared victory when my wife complained that I froze some of the vegetables!

Ultimately, these fridges perform just like I do – great when it’s nice and cool or just warm, and struggle when it’s hot. I doubt that any one of these mods would have made such a difference, but rather it is the cumulative effect of all of them.
Ok just what I needed . Where can I purchase the snip the tip thermistor ? Wish you had some pics . Any more info would be appreciated . Pat
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Old 06-24-2015, 08:18 PM   #35
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Hey Pat, the photo guide I referred to is here http://lakeshoreimages.com/PDFs/BafflePDF.pdf

Google snip-the-tip and you'll see their only product which I used.

If you decide to do this, I'll help any way I can.
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Old 06-24-2015, 08:49 PM   #36
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Glad to hear that after all your hard work it has made some improvement!!
I agree with you that no one mod will get the fridge to preform noticeablly better but a series of several mods will make at least some improvement.
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Old 06-24-2015, 09:08 PM   #37
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Glad to hear the problem with your 4.3 is fixed! Does the 3.0 work any better than the 4.3?
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Old 06-24-2015, 09:15 PM   #38
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Here is a picture of the rear of Rich's set up he sent to me to post for him
here is the link for the thermistor http://www.snip-the-tip.com/cgi-bin/articca.cgi
Attached Images
File Type: jpg 20150615_191106_resized.jpg (178.8 KB, 76 views)
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Old 06-24-2015, 09:18 PM   #39
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Glad to hear the problem with your 4.3 is fixed! Does the 3.0 work any better than the 4.3?
Well yeah, we had no problem with ours, however it is about 50% smaller.
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Old 06-24-2015, 09:30 PM   #40
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Originally Posted by Zardoz View Post
Hey Pat, the photo guide I referred to is here http://lakeshoreimages.com/PDFs/BafflePDF.pdf

Google snip-the-tip and you'll see their only product which I used.

If you decide to do this, I'll help any way I can.
Thanks I did find the web site . There is another I found too Dinasoar thermistor which is better ? Also at site for yours they say to scroll go down and get for our model ? Or did you get something else I want it colder not sure which one to get . Pat
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