How much does you ARB fridge temperature vary (1 Viewer)

[REKCUT]

Lets try this in a shorter version. How much does your temperature vary in you fridge one you set it and get it to temp. Will it hold at what you set it vary several deg above and below the set temp?

 

[george_tlc]

Seems to stay reasonably close to the set temperature when I ran it from 70F to 110F range on a couple of week trip. Never had issues during the trip - food safely cold and beer just right. We were away from towns so what was in the fridge had to feed 2 of us for the entire time, so would have been easy to detect if there were 'storage' issues a week or more into the trip.

You'll get temperature variation in the cabinet depending on what's at the bottom of the fridge versus what is in the top or in the 'dairy' area but that's assumed since there is no active motion of air within (no fan).

There's hysteresis variation as well since the fridge cycles.

Never seemed like an issue to me, but then I'm not expecting house fridge temp stability in something that is portable, is being opened and a significant quantity of thermal contents are being replaced (e.g. pull out 3 or 4 cold drinks and replace with warm/hot ones).

The ARB also has a way to calibrate the temperature reading (and hence control set point) that is in the service manual if your measured internal temps are significantly off from the displayed value once steady state is reached in the fridge.

cheers,
george.

 

[REKCUT]

Not worried about temp calibration. I have an issue with the fact without opening the lid the temp will have a 8 to 10 deg swing. The compressor kick on and stays on until it gets 4 to 6 deg colder than the setting and then won't come back on till the temp reaches 4 to 6 deg above setting. On my older fridge I can set the temp to just above the freezing point of drinks and it will hold. This one runs in a 8 to 12 deg swing

 

[e9999]

not ARB but for context my Edgestar "temp" is varying by about 2 or 3F below and same above set point, as shown on the built-in display but also with direct inside temp measurements. And I found the display and inside temps to match reasonably well -within a couple of F. Interestingly, these swings are smaller than my house fridge, but I'm sure the top lid helps with that. The dynamic variations are a function of the control algorithm implemented (on/off, partial power etc).

Keep in mind, though, that the food inside has thermal inertia so it's not because the air inside or the wall of the fridge (likely where the probe is) temps vary by such and such amount that the food does too.

 

[george_tlc]

Not worried about temp calibration. I have an issue with the fact without opening the lid the temp will have a 8 to 10 deg swing. The compressor kick on and stays on until it gets 4 to 6 deg colder than the setting and then won't come back on till the temp reaches 4 to 6 deg above setting. On my older fridge I can set the temp to just above the freezing point of drinks and it will hold. This one runs in a 8 to 12 deg swing

Do you have the fridge full or just full of air?

I haven't seen those kind of swings.

cheers,
george.

 

[REKCUT]

For reference, I ran both my old fridge and new one side by side in the same truck a week in big bend texas. Temps ranged from high 30's for a low and high 80's for highs. Both fridges were anywhere from 50% to 75% full depending on what was going on during the trip. The 8 year old one just sat at 29 deg. The new one would do like i said and drop down to 23, compressor off, then would not kick back on till 33.

The new fridge is a replacement for one i bought and tried for a week around the house before the trip and it would go drop down to 15 deg before rising back up to 33. That one i got replaced by ARB but this one is still not staying consistent. I am wondering if its worth going back to ARB again or if they are using a different circuit board now that less sensitive to changes.

 

[george_tlc]

Yeah, talking to ARB is your best bet - they SHOULD know what the average temperature range would be during operation. Finding out where the temperature sensor is may help with understanding what is going on. What model/size is this?

cheers,
george.

 

[REKCUT]

50 qt. When i talked with ARB they really didn't seem to offer much advice. Just replace. said it seems odd. Thats why i am trying to see if this is the norm for new ones or if these two are an anomaly.

 

[NMBruce]

have a 50qt ARB, I set the temp to around 29, nothing is freezing and the read out is always around 28-33

 

[REKCUT]

So yours swings 5 to 6 deg. How old?

 

[GLTHFJ60]

Why does this matter? I'm certainly not checking the fridge to ensure that it's keeping right at X temperature, just that the fridge is powered on and either keeps stuff frozen or in the "food safe" temp range.

Why is a 8-10 degree swing a problem? It's probably more energy efficient to let the fridge swing a bit. It's also possible that there is a more sensitive thermometer in the newer fridges, meaning that the older fridges did the same thing. Do your test with a mechanical thermometer inside the fridge and see if you see the same behavior.

 

[george_tlc]

^ agree.

I looked at the service manual and the thermistor is inserted below into some 'hole or something' since the manual shows liberally coating the thermistor probe head with thermal compound - to obviously provide better coupling between the thermistor and the place it inserts into the outside surface of the cooling shell.

So, not the optimal place to sense internal temperature and also dependent on how much thermal goop was added at time of assembly...

I can easily imagine some variation in 'sensed' temperature. Not the way I would have designed the thermal coupling/sensing.

cheers,
george.

 

[REKCUT]

I like the fact that i can keep my fridge on the edge of freezing. Ice cold drinks. A swing like this will cause bottles to bust. When all the units i have been around to this point hold a constant temp and my new one doesn't then I would like to know why. It also take more energy to drop the fridge down to 23 deg when I want it set at 27.

 

[NMBruce]

So yours swings 5 to 6 deg. How old?

about a month old, I plan to get a cover for it.
Also is the fridge sitting in the back of the GX470 and I haven't really checked when going down the highway and constant power to it. I check it from time to time.

 

[GLTHFJ60]

...A swing like this will cause bottles to bust...

If it's actually swinging that much. I bet the condensor coils swing that much but the interior temp of the fridge doesn't. Try with a mechanical thermometer inside and see if you see the same swing.

 

[REKCUT]

I will try with a temp probe. I assume if that was the issue then ARB would not have replaced my first unit. The difference in run time is night and day when you have the old one and the new one plugged in side by side. The older one will kick on and off for shorter periods of time while the new cycles on much longer runs. What initially brought it to my attention is the remote display that i got with the new fridge. While driving you can monitor your fridge temp. Its a nice feature when your packed to the hilt and running in hot climates.

 

[GLTHFJ60]

Ok, that makes more sense. I did get the new remote display but haven't wired a socket for it yet.

Definitely let us know if you see the same issue with the temp probe. I got my ARB 50qt 3 months ago, so maybe I'll have the same problem.

 

[1911]

I have to set my ARB fridge at least 7 degrees lower (indicated) than where I really want it, i.e. if I want it to freeze, I have to set it like 24 or 25F. There is a way to re-calibrate them, but I haven't tried it yet.

 

[sean2202]

have a 50qt ARB, I set the temp to around 29, nothing is freezing and the read out is always around 28-33

This is exactly what mine is consistently running in the house or in the car. Thinking about putting a temp gauge in there to see what is exactly. Purchased mine last summer 50qt as well.

 

[79bj40]

I was just looking into this before taking a trip next week and came across this thread.

I see the same thing in my ARB - about a ten degree temp swing per cycle.

My old 20 year old Engel has less than one degree swing. I keep the food in the Engel and the drinks in the ARB.

See attached screenshots from the bluetooth sensors.