ARB 50 Quart Fridge Freezing Up, Won't Keep Preset Temp (1 Viewer)

[Dissent]

I have a new to me (used) ARB 50 qt fridge. I don't know it's history. I plugged it in, set it to 41 F and it went down to 41 F in about 10 minutes. Then the issue arose....it kept going. I unplugged it at 32 F.

I suspect this is a relatively common issue. Maybe a bad thermostat? Anyone have any advice how to address this? I already have an email into ARB tech support.

 

[TXSunDevil]

Have you filled it with any food or liquid and let it stabilize? If I set mine at 29 it will go from 25-32. I would want to see it cycle a few times with something inside before going any further.

 

[REKCUT]

My first arb would set at 29 and it would vary 2 deg up or down. Purchased a new one year and a half ago and it would cycle up and down 6 deg each way. Exchanged it under warrantee for one that goes up or down 4 deg. ARB says this is normal. I would fill with something and also put a fridge thermometer inside for a true reading. 5 fridges in our group and they all vary in displayed temp to actual temp. Set mine at 29 and it will freeze water if i only have a couple bottles in it. But if its half full or more its perfect. Another one in our group sets his at 33 and another at 24.

 

[cruiserdan]

I have an ARB fridge and an Edgstar. Both are more stable when they are full. I also have a small RV fridge fan that I toss in to balance out the temperature. The fan I use runs on 2 D batteries and was around 12 bucks at Camping World.

 

[Dissent]

Thanks for the info guys. I'll try to load it up with water bottles and watch it. I suspect the thermosister in the floor is bad. After doing some research, these fridges have a "fail to freeze" setting should the thermosister not read correctly. Nice touch. Here's a nice writeup I found about this issue and how to fix it. I'm going to pester ARB for a replacement thermosister bulb.

ARB cords and fridge mods - Page 3 - Expedition Portal (posts #23 to #27)

 

[george_tlc]

The temp sensor on these fridges aren't precision parts and the location of the sensor is 'somewhere' near the outside of the cavity. Lots of variability there since it will be affected somewhat by ambient conditions.

You can also 'calibrate' the temp sensor/display (on the ARB) to at least have the displayed temp closer in tune with the actual temperature. But you'll still have variation of sensed temperature due to the location of the sensor.

cheers,
george.

 

[cruiserdan]

I replaced the thermister in my Edgstar and that was an adventure.

 

[george_tlc]

For grins

http://www.taskled.com/mud/ARBFridgeFreezer_serviceManual_8-2013.pdf

cheers,
george.

 

[Dissent]

I spoke with I spoke with ARB this afternoon, they're going to send me a new thermistor. It just depends if it's new enough to replace from the rear by the compressor or do I have to cut a hole in the bottom. I'll let you know.

 

[REKCUT]

Did you ever fill it and see if it stabilized?

 

[Dissent]

I didn't get a chance, had to work late last night. I will tonight though.

I did confirm that when I removed the 12 screws and the vented cover that there is a tube where the thermister wire runs to the center of the cooler floor. The tube is in the lower left corner, looking at the back of the fridge. There's some black goop plugging the tube and a white screw clip to secure it. According to ARB, this model can be replaced by pulling the wire out and inserting a new one.

 

[george_tlc]

As per the manual I posted above, the 'goop' is a thermal paste to provide a good thermal path between the thermistor and the tube that contacts the bottom of the housing.

cheers,
george.

 

[Dissent]

As per the manual I posted above, the 'goop' is a thermal paste to provide a good thermal path between the thermistor and the tube that contacts the bottom of the housing.

cheers,
george.

Thanks for that manual! They're sending me a free replacement thermistor. Awesome customer service!

 

[Dissent]

As per the manual I posted above, the 'goop' is a thermal paste to provide a good thermal path between the thermistor and the tube that contacts the bottom of the housing.

cheers,
george.

ARB said I didn't have to add any thermal paste but I figure I'll just use the thermal paste from my computer CPUs if need be.

 

[TXLX100]

@Dissent Did you try to calibrate the digital display? I have a dometic (made by ARB or vice versatile) and the temps were all over the place, someone told me how to calibrate the temp display to get closer to actual temps (hold down a series of buttons ?).... It was not in the owners manual.

 

[george_tlc]

^ I have posted the ARB service manual, it includes the adjustment/calibration steps. Which likely need to be done once dissent replaces the thermistor with a new one.

cheers,
george.

 

[Dissent]

I did try calibrating it after @george_tlc posted up the manual (Thanks!) And will have to calibrate again once the sensor is replaced. The initial calibration didn't help.