Fridge Performance

[reace]

STOP THE PRESSES!

Although the baffle may contribute a small bit to the fridge cooling, I am now convinced it is not the big problem. I encourage everyone to hold off on the baffle install (unless you are bored) for a few more days.

Tammy and I are currently travelling in a 5.0TA. This is one of the units I was playing with in the yard trying out different methods of fridge installation. This unit has insulation packed in around the sides and top of the fridge, baffle and exterior 'Texas' fan. Seemed to perform ok in the yard...not so on the road.

Mike from Smart RV Products was kind enough to ship one of the Fridge Fix fan kits to me on the road in Oregon to play with along the journey.

Oddly, the two day drive down the coast to Bandon OR, the fridge held fine, but once we reached Bandon, it started to go downhill...and it wasn't that hot on the coast.

As we headed inland, it just can't keep up. I have done everything possible on the installation side to achieve the best performance. While in Bandon, I had a close up look at the install of the Dometic fridges in the Casita trailers, and they have much the same gapping as our install without baffles. The owners are quite happy with the cooling of their fridges!

What am I missing?

We are currently in Eastern California with temperatures in the low 30's and the fridge is holding in at around 5 degrees...with ice packs in the fridge.

Unfortunately the Fridge Fix is not helping...and today I think I figured it out. I stopped and bought an infrared thermometer so I could see what the temperature is on the cooling fins.
First of all, let me start with...I have two thermometers, one is a digital wireless which is nice...the other is a horizontal unit with the red stuff (?) that shows the temp and stays in fridge. Digital unit reads about 1.5 degrees C higher than cheap unit.
Ok, fridge set on max, inside temp reads 5 degrees, so does the fins. One hour later, the fins read 0 degrees. I have caught it as low as -5 at times, so I know if it would stay there, the Fridge Fix fan would definitely have some cold to move around the fridge interior.

Today I had another lengthy conversation with one of the higher- ups at Dometic. With all the information I have gathered, we have to be able to come to a solution, because so far, nothing suggested has really worked...effectively. I am now convinced that the thermistor is not set correctly or is simply failing. Dometic is going to overnight some products to me tomorrow to try. As I kind of butchered the one in this fridge trying to see any change, I will start with a new replacement thermistor. Hopefully it is as simple as a defective unit. I also asked for a thermistor out of a different fridge that I can splice in, as maybe these are just not set properly. Dometic mentioned they did have a booster for the thermistor for fridges that simply could not cool enough. I am hopefully getting one of those too! He was not sure if they were still available.

So, after all that, if in fact the thermistor is the problem, lets try that fix before we jump into the baffle fix...because it isn't helping right now.

I will keep in touch

Reace

[dave macrae]

That's good that you seem to be getting somewhere

[Kountrykamper]

Thanks Reace!! We had canceled our trip for this weekend and I was going to install the baffle Saturday.

This would make more sense because like I had mentioned before our Casita was vented terrible with just as much room between the wall and fridge and would freeze food.

Keep us posted.

[tractors1]

Did Dometic say what the standard resistance is for the thermistor they're using? Usually specified at 25 degrees C. Seems a bit hard to believe they may be installing a poor choice. Precision lab quality thermistors are under $30........

[Rossue]

Bad thermistor was deemed the problem that caused a fire in my 2 year old Thermador wall oven last year as the broiler would not turn off at temperature . But the tech was wrong...he left without properly testing it and the same problem remained. He had been sent by the Extended Warranty company and turned out his firm wasn't on Thermador's authorized repair list. Bottom line: new motherboard fixed it.

[Jubal]

Product Listings for Snip The Tip
http://www.snip-the-tip.com/cgi-bin/articca.cgi
A possible option ?

[alanmalk]

Originally Posted by Jubal

Product Listings for Snip The Tip
Dometic Thermistor Repair Kit
A possible option ?

In true internet spirit, following the above link to another - I found this tidbit: "Thermistor failure is a common issue in RV refrigerators and generally causes the temperature to fall too low".

Source: How to Check a Thermistor in an RV Refrigerator | eHow

I can't comment on the accuracy of the above statement, but will note that there is a possibility of falling into the "too much information" trap.

--
Alan

[rbryan4]

Originally Posted by alanmalk

In true internet spirit, following the above link to another - I found this tidbit: "Thermistor failure is a common issue in RV refrigerators and generally causes the temperature to fall too low".

Source: How to Check a Thermistor in an RV Refrigerator | eHow

I can't comment on the accuracy of the above statement, but will note that there is a possibility of falling into the "too much information" trap.

--
Alan

I would suggest allowing Reace to test with the replacement thermistor from Dometic to see if that is the issue in the first place. These fridge threads are chasing their tails at this point.

[alanmalk]

Originally Posted by rbryan4

I would suggest allowing Reace to test with the replacement thermistor from Dometic to see if that is the issue in the first place. These fridge threads are chasing their tails at this point.

Actually, that was exactly my point. You can drive yourself nuts looking at all the factors (altitude, baffles, thermistors, gas pressure, interior air flow, fan regulators, etc, etc.). After a year or two we can all become refrigeration engineers, OR we can let Reace do some real-world testing and find the eventual solution. Not to discourage anyone else from making mods and testing, but just to emphasize that there are no limits to the time and energy that this project might take.

--
Alan

[markvt]

Originally Posted by rbryan4

I would suggest allowing Reace to test with the replacement thermistor from Dometic to see if that is the issue in the first place. These fridge threads are chasing their tails at this point.

I will second that Reace has way more pull with Dometic them we as individuals to get this problem fixed right.

[rbryan4]

Originally Posted by alanmalk

Actually, that was exactly my point. You can drive yourself nuts looking at all the factors (altitude, baffles, thermistors, gas pressure, interior air flow, fan regulators, etc, etc.). After a year or two we can all become refrigeration engineers, OR we can let Reace do some real-world testing and find the eventual solution. Not to discourage anyone else from making mods and testing, but just to emphasize that there are no limits to the time and energy that this project might take.

--
Alan

Not meant as a criticism Alan....
Just suffering from information overload on the fridge topic.

[escape artist]

Hi: rbryan4... Overload on the fridge topic... is to much BEER!!! Alf
escape artist N.S. of Lake Erie

[Jim Bennett]

Originally Posted by escape artist

....to much BEER!!!.

I am unfamiliar with this concept.

[Klem]

Hopefully no one will be discouraged from posting their tests, ideas, and brainstorming ideas regarding solving the refrigerator issue(s). Folks that are overloaded may read other topics.

“We always hope for the easy fix: the one simple change that will erase a problem in a stroke. But few things in life work this way. Instead, success requires making a hundred small steps go right - one after the other, no slipups, no goofs, everyone pitching in.”
― Atul Gawande, Better: A Surgeon's Notes on Performance

[jamie beers]

Outside temperature today is 78 degrees. Inside fridge temperature is 45 degrees. I'm thinking of just turning off the fridge to save propane, and wait until Reace conjures up some magical solution.

[gbaglo]

In the meantime, I found that moving freezer packs from the freezer to the main compartment helps a lot. The freezer still freezes even if the fridge isn't reaching 42 degrees.

[azjack]

We are now in more normal weather, AZ is not normal. We had 100* days traveling in N CA but cool nights and our 6.7 worked fine as long as we turned on the fans during the hottest part of the day. Single digit freezer and 30's in the fridge at 5 bars. When we arrived in the SFO area, Candlestick Park we have to turn the fans off and at times go to 4 bars with a high of 65* and a low of 60* or so and still have freezer at 4 or 5* and fridge in the low 30's. Guess we may have to move back here again, except for all of the people and crowds. We will be getting our new fan unit Wed. and hope to install it while in San Diego and compare it to the single fan I have in the fridge while crossing the desert and maybe that will also reduce the frosting over of the cooling fins.
Jack

[Rossue]

Originally Posted by reace

STOP THE PRESSES!

Although the baffle may contribute a small bit to the fridge cooling, I am now convinced it is not the big problem. I encourage everyone to hold off on the baffle install (unless you are bored) for a few more days.

Tammy and I are currently travelling in a 5.0TA. This is one of the units I was playing with in the yard trying out different methods of fridge installation. This unit has insulation packed in around the sides and top of the fridge, baffle and exterior 'Texas' fan. Seemed to perform ok in the yard...not so on the road.

Mike from Smart RV Products was kind enough to ship one of the Fridge Fix fan kits to me on the road in Oregon to play with along the journey.

Oddly, the two day drive down the coast to Bandon OR, the fridge held fine, but once we reached Bandon, it started to go downhill...and it wasn't that hot on the coast.

As we headed inland, it just can't keep up. I have done everything possible on the installation side to achieve the best performance. While in Bandon, I had a close up look at the install of the Dometic fridges in the Casita trailers, and they have much the same gapping as our install without baffles. The owners are quite happy with the cooling of their fridges!

What am I missing?

We are currently in Eastern California with temperatures in the low 30's and the fridge is holding in at around 5 degrees...with ice packs in the fridge.

Unfortunately the Fridge Fix is not helping...and today I think I figured it out. I stopped and bought an infrared thermometer so I could see what the temperature is on the cooling fins.
First of all, let me start with...I have two thermometers, one is a digital wireless which is nice...the other is a horizontal unit with the red stuff (?) that shows the temp and stays in fridge. Digital unit reads about 1.5 degrees C higher than cheap unit.
Ok, fridge set on max, inside temp reads 5 degrees, so does the fins. One hour later, the fins read 0 degrees. I have caught it as low as -5 at times, so I know if it would stay there, the Fridge Fix fan would definitely have some cold to move around the fridge interior.

Today I had another lengthy conversation with one of the higher- ups at Dometic. With all the information I have gathered, we have to be able to come to a solution, because so far, nothing suggested has really worked...effectively. I am now convinced that the thermistor is not set correctly or is simply failing. Dometic is going to overnight some products to me tomorrow to try. As I kind of butchered the one in this fridge trying to see any change, I will start with a new replacement thermistor. Hopefully it is as simple as a defective unit. I also asked for a thermistor out of a different fridge that I can splice in, as maybe these are just not set properly. Dometic mentioned they did have a booster for the thermistor for fridges that simply could not cool enough. I am hopefully getting one of those too! He was not sure if they were still available.

So, after all that, if in fact the thermistor is the problem, lets try that fix before we jump into the baffle fix...because it isn't helping right now.

I will keep in touch

Reace

Any update? We know you've gone to a 2 door model recently. Is there anything new regarding the original 6.7 performance issues?

[Jubal]

Originally Posted by Rossue

Any update? We know you've gone to a 2 door model recently. Is there anything new regarding the original 6.7 performance issues?

And the 4.3 refer ?

[Jubal]

BTTT and looking for answers for those of us that already have trailers.