Isotherm Fridge warms, not cold all time? - Tab 400 2024 upgrade finished

vttj · May 4

I did a bit of searching and got a few ideas but thought to create a post to see if I am missing an easier fix on our fridge or its something I am not doing right. Our Isotherm 130 in the Tab 400 2024 at times we will loose the fridge temp (get near 50 deg F). To improve the issue I installed a fan inside the fridge, a wireless thermometer to monitor, turned dial all way up, and tried to keep door stacked with cold drinks but we still lost it again few weeks back. Also made sure the door is not in vent so it doesn't come open while driving. I notice the issue more when we get the sun on the driver side of the camper either when driving down road or at campsite on shore power. I am thinking to put a small fan at the top back of cabinet to assist with moving air off that back wall behind fridge to the front grill over fridge. Found an usb fan and temp controller on amazon for 16 dollars and reading online seems that 25 CFM is all I need to assist with the intended design of airflow and not short circuit the airflow. Also will keep a small fan inside fridge to keep air moving. Anyone already make a similar change and if it helped?

Anything obvious I am missing? I expected this fridge to keep up better but maybe they just don't have the power.

Image: https://us.v-cdn.net/5021717/uploads/editor/0k/t554g55elt1v.jpg

Image: https://us.v-cdn.net/5021717/uploads/editor/6r/r8hocafbf2fg.jpg

B0atguy · May 4

Try removing the freezer drip tray when using the fridge . Make a world of difference . Just make sure you re-install it when the fridge is turned back off and emptied or the fridge compartment with get "rained on" when the freezer thaws . This trick worked wonders in keeping the Isotherm "cold" in or 2024 400 .

I think NuCamp needs to put a vent / fan to the outside in that Isotherm compartment to relieve the heat build up . The fridge does transfer a lot of heat to the cabin when it's hot out . That said , the drip tray removal trick really does help.

I also "pinned" the door closed while traveling . A few times I noticed that the door would crack open into the vent mode when traveling , especially when the door was loaded up with drinks.

vttj · May 4

Thanks @B0atguy

vttj · May 6

Finished the upgrade.

Amazon.com: ELUTENG USB Fan 120mm with Digital Temperature Controller, 5V USB Powered PC Computer Fan 1500RPM 3 Adjustable Speeds Electronic Cooling Lufter with Metal Grill for Laptop/TV Box/AV Cabinet/PS5/Router : Electronics
Used this controller but not the fan. Can buy controller only but its in Chinese and with out fan for only 3 dollars cheaper. This version is English but its easy and could have used the Chinese version They are both in deg C. I have it come on at 88 deg F and turn off at 84 deg F. Just laid it all behind stereo and if need to adjust fan speed or temp settings can just pop stereo out.

I used this fan instead as needed to fit above fridge. Did add some material and double sided tape above the outlet duct to act as part of air duct and limit recirculation.
Amazon.com: AC Infinity MULTIFAN S2, Quiet 120mm USB Blower Fan with Speed Control, UL-Certified for Receiver DVR Xbox Modem AV Cabinet Cooling : Electronics

Pic shows thermocouple in back but it is to high in this pic just near compressor. I went back after testing and lowered about 8 inches placing also more center of cabinet. Working much better giving more accurate read of cabinet. After a smoke test appears I am getting a good draw across top with fan on speed setting 2 which is aprox 20cfm. Hopefully this will help.

In addition applied some aluminum spaced about 1inch off back wall to try to cheat out a few more deg when sun is sitting on camper while going down road. Also found that the cut out in the wall for the antenna is a 3 inch cut out (not shown in picture but you can see it in top right if you stick your head in the cabinet). They removed the entire insulation for 3 inches. I added a 3 inch round hard foam board insulation back.

Image: https://us.v-cdn.net/5021717/uploads/editor/ic/2fxvs9m0prwb.jpeg

Image: https://us.v-cdn.net/5021717/uploads/editor/vw/3gg409v7ooce.jpeg

Image: https://us.v-cdn.net/5021717/uploads/editor/if/rkdi3cxtbc4c.jpeg

vttj · May 6

Also added the 80mm version of ac infinity fan to the inside fridge to help with circulation and will just plug into stereo when going down road. Got tired of messing with batteries.

I still plan to follow others advice and remove the drip tray also when fridge is stocked and ready for next trip.

I keep you posted during the summer to see how it does.

SavvyNurseCamper · May 16

Hmm are you aware of the intelligent Temperature control kit? I spotted it in fisheriesssupply.com . It's made for the Isotherm 130 refrigerator . Supposed to use a soft start feature on the refrigerator and has a Econ mode that is Supposed to drop power consumption by 40 percent.

vttj · May 23

Hi thanks for sharing the info on the Isotherm ITC thermostat. I have come across that as well.

From what I understand, it improves temperature regulation and helps balance energy draw, especially for those running on solar. In my case, I’m almost always on shore power, so power efficiency isn’t really the issue.

The problem I’m seeing seems more related to heat buildup behind the fridge. When the sun hits that side of the camper, the temperature in the rear cavity gets quite high. At that point, the fridge is running continuously but still struggles to keep up with the temperature difference.

ssheets9 · June 30

I pulled the drawer out and installed a thermostat controlled or manually controlled fan there. I made a frame and held the fan in place with parachute cord to hopefully reduce noise transfer to the cabinet. Fan link:

http:// https://www.amazon.com/dp/B0C33JYFPL?ref=ppx_yo2ov_dt_b_fed_asin_title

vttj · July 3

nice setup

Ikanizer · July 3

https://tab-rv.vanillacommunity.com/discussion/comment/222166#Comment_222166

DId you cut a hole for the fan to discharge the hot air? I tried mounting two very small cooling fans inside the exhaust grill above the refrigerator. I wired them to come on whenever the fridge compressor energized. I was not happy with the volume of air they pushed and after a few days the bearings failed and they were so noisy I had to disconnect. I also added insulation to the walls around the fridge. The performance of this refrigerator is the worst thing about my trailer.

How is your system working?

ssheets9 · July 3

Thanks for your interest. I have not camped yet with the fan upgrade. I have only tested it at home.
I had this same fan in a previous camper, not a Tab, and it was quieter than the original refig cooling fan and did a great job.
As far as air flow, I have the fans puling air from the vents from the top of the open storage area that is under the pull out drawer. For the exhaust, I’m using the metal vent at the top of the frig. To increase the air flow I did cut out every other wood vent slot below the drawer. By holding my hand at the vent at the too of the frig, I can feel the air flow.
When I camp next, I will also test removing the drip pan from under the freezer while camping. I have several trips planned in July of 26. I’ll provide an update on the fan and if removing drip pan made any difference.

vttj · July 6

Out of my mods I did above the one item that I think made the biggest impact is removing the drip pan.

ssheets9 · July 8

Here is un update on how the fan mounted behind the drawer under the frig is doing. I have a 24 Tab 400 Boondock with the Isotherm elect frig. I have a wifi thermometor in the frig. See photos for temperature ranges. I’m at 8600’, frig side of camper is facing west. I have electric. Air conditioning set to 75. Thermostat for ancillary fan is just above the frig on the bathroom side.

Day 2 of camping, 7/7/26. Fan set to come on at 85 degrees. Fan comes on late morning. If I set to 90 degrees, fan went off. Reset to 85. Frig set to 5 1/2. At noon sunny and 91 degrees. Sun just starting to hit the west side of camper. Removed tray from under freezer. Turned frig temperature to 5. At 4 PM fan turned itself off. Outside temp dropped 5 degrees and clouds rolled in. At 10PM set frig temp to 4.5 and re-installed tray under freezer. Turned ancillary fan off.

Day 3 of campinf. 7:8/26. At 8 AM opened rrig for breakfast. Turned frig to 5. Set ancillary fan to 85 degrees. Sunny and 88 degrees. At 1PM the fan was running. Set temperature to 90, fan turned off. Re-set back to 85 degrees.

I’m studying the screen shots of the temperature history now. Things are much better than my last trip. Hope this info, while detailed, made sense.

B0atguy · July 8

https://tab-rv.vanillacommunity.com/discussion/comment/222240#Comment_222240

BINGO !

After figuring out to remove the freezer drip tray while using the fridge , our biggest struggle is to keep everything from freezing in the fridge . We usually have the thermostat turned down to about 2.5 - 3 and it usually keeps temps in the 35-40 degree range. We have even had some cans of boat sodas on the lowest door shelf burst , cause we had the fridge turned down too a little too low .

On a side note - I really think Nucamp should have put a small fan that vents to the exterior in the space behind the fridge . Kind of like a range fan or something.

Ikanizer · July 12

This is great information. We have been on the road since late May mostly boondocking. I left my freezer tray at home in Texas. Its all about ambient temperature inside the trailer and behind the refrigerator. We are in Alaska and haven't seen many days above 70 deg. Refrigerator has no problem maintaining under 40 deg when set between 4 and 6 1/2. We've had a little bit of freezing but no real damage (yoghurt with a little ice on top). When traveling from Texas to California and up the coast the refrigerator struggled during warm days to keep below 40. Even here in cool Alaska it is a power hog at 2+ amps almost continuously.

I need one of those BT temp monitors can you include a link?

RTWCTS · July 12

I've been wanting to get into the fridge cabinet to do a mod and seeing the pics in your original post @vttj gave me great clarity. I especially appreciate how you used plywood to make a platform to move/support the fridge outside of the cabinet. Thanks for that!

On a side note, we're on team defrost tray out of the fridge (unless defrosting).

ssheets9 · July 12

Link to BT thermometer

https://www.amazon.com/dp/B097HF322L?ref=ppx_pop_mob_ap_share

SavvyNurseCamper · July 12

@B0atguy Please post pictures on how you remove the freezer tray!! Make it easier for the rest of us to do so! I want to do so for mine!😉

ssheets9 · July 12

It is the plastic tray that catches water as you defrost the freezer that people are removing. Just place your hand under it. Frool for the finger slot. Pull/ slide forward.

B0atguy · July 12

https://tab-rv.vanillacommunity.com/discussion/comment/222309#Comment_222309

Just slide out the tray under the freezer section as ssheets9 has shown in a picture . Very easy .

Just dont forget to put it back in as soon as you turn off the fridge or else you will have a wet fridge compartment as the freezer thaws !

Marceline · July 13

https://tab-rv.vanillacommunity.com/discussion/comment/222307#Comment_222307

I use these at home too, and it gave me an early warning that my home fridge was dying.

SavvyNurseCamper · July 13

@B0atguy Thank you for the picture! @Marceline I have saved that . I bought a simple bluetooth arrangement from Amazon so I don't have to open the door to see if it's cooling. If that should fail in the future will buy that one! How long do the batteries last?

Isotherm Fridge warms, not cold all time? - Tab 400 2024 upgrade finished

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