Monitor refrigerator temperature

Refrigerator, stove, furnace, water pump, air conditioner, microwave, water heater, fans, lighting
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Ernie
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Monitor refrigerator temperature

Post by Ernie »

Three years ago, I bought an alarm clock with date and interior/exterior temperature monitor. I place the exterior temperature sensor in a ziplock bag to keep it clean, and put this inside the refrigerator. The clock/temperature indicator is usually kept in the small tray on driver side on top of the engine compartment of my 1993 B190. I can easily read the interior temperature of the frig at any time without leaving the drivers seat. The sender and receiver use AA batteries, I use rechargeable ones, but only need to recharge every few months. (I power camera, portable MP3 player etc with rechargable AAs). Now you can buy the "Atomic Clock" type that updates the time and date automatically for you. Some models come with ability to indicate the maximum/minimum temperature measured. This allows you to be confident your food has not gotten too warm, and is very helpful in adjusting the temp without having to open the door. Cost is about $15. I bought my old one at Big Lots, and like it due to ability to press large snooze alarm button on top which causes dial to light up - so you can read without disturbing others at night. WalMart has a good selection also.
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skater
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Post by skater »

I do something similar but without being able to see it from the driver's seat. :)

I bought an indoor/outdoor thermometer, one that has the wire for the outdoor sensor. The outdoor sensor is in the freezer, and I keep the rest of the thermometer in the fridge, so I can see what the temperature is in both parts.

However, since I've gotten smarter about using the fridge - starting it the day before a trip, opening the awning to protect it from the sun as much as possible, and turning on the coil fan mine has - I haven't had any problems with it. The idea is to keep those coils as cool as possible.

Oh, I also have one of those little fridge fans inside it - they're powered by two D-cell batteries and cost $10-$15. That seems to help, too, and they run silently.

I just made reservations for a camping trip to Indianapolis in July, and I requested a site that is oriented so that the fridge is out of the afternoon sun. Last time I was there the fridge was in the hot sun most of the day, and I hadn't yet learned the tricks above, and it destroyed all kinds of food. I'm not expecting a problem this time with what I know now.
1991 Airstream B190 - bought, 2005; sold, 2011; bought 2017
1995 Airstream Excella 30' trailer

WBCCI #13270, Washington, DC Unit
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Ernie
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Post by Ernie »

I should have mentioned the fan for use inside the frig. It does a great job of helping to keep uniform temps and lower temp in frig in hot weather. Mine is a small squirrel cage type, runs on D cell alkaline battery, which lasts about 3 weeks. From WalMart RV section at about $15. I keep mine in the lower right front corner, which seems to work the best for me. I keep my temperature sending unit for my digital thermometer in the lower left corner of door tray, blowing the cold air up to the top where it is deflected across the top of the frig. and the cold coils/plates before returning to the fan.
The first time you use your frig, you should plug in and run it on your house current/AC AT LEAST a couple of days before your trip, and more if possible. This will allow you plenty of time to determine the proper thermostat setting before your trip. Do not load PERISHABLE food untill after after you have stabilized the temp at 40F in the fresh food section.
Having the frig loaded will help to get the proper setting, but you will have to allow at least 4 hours for the temp to stabilize between adjustments. You should not run the frig on max setting, this will only result in frozen food in fresh food section, (Once the frig. reaches 40F it will continue to run instead of cutting off.) After you have found the setting that maintains frig at 40F, note the thermostat dial setting. I placed a dot on mine with a pencil, so I can remove it later if desired. Then, next time you take a trip, you know exactly where to start. If you are in a hot climate and having trouble maintaining 40F, turn the thermostat down a little so that at night or between door openings the temp will be lower, giving frig a head start on the hot day ahead, or the effects of frequent door openings. Of course try not to open door often or leave it open for more than necessary. Try to buy cold beverages and put in frig before they warm up. Also, load warm/room temp beverages at night before bedtime, not in the hot part of the day. I have a tuperware container that fits snuggly under the bottom shelf, which seems to help prevent freezing of ready- made bagged salad.
In hot weather I always try to find a campsite which shades the frig in the afternoon. Two years ago in Las Vegas it was 110F. Even running on campground AC could not keep frig at 40F as recommended. I did discover that opening the louvered frig vent/access door (which is located outside the RV), and propping it open and allow more air flow helped a bit.
Skater, any chance you could post a few pics of the fan which is in the outside area of your frig?
I confess I am guilty of running my frig on propane while driving in hot climates. The 12 volt sysyem just can't keep cool on the road. I think the greatest danger is not from having a wreck, but from forgetting and fueling up while the frip is on propane. Perhaps a fan in outside area would allow 12 volt system to do a better job?
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skater
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Post by skater »

Ernie wrote:Perhaps a fan in outside area would allow 12 volt system to do a better job?
Sure, I can post some pics. However, I'm not sure how much the fan would help while on the road, because I think there'd already be impressive airflow through there. I've never tried to run it on the road but there's no reason it wouldn't work, and it may help a little.

Originally the fan on mine was wired in with a temperature sensor, so it would only turn on when it got above a certain temperature (possibly 120 degrees). I didn't know what the switch inside was for until that trip to Indy the first time; it's wired so that you can turn the switch on, but the fan itself doesn't run until the temperature hits 120 degrees, at which point the light in the switch comes on. I bypassed the temperature sensor and just control the fan directly now; I leave it run on hot days.

You're right about the 12 volt mode - it's pretty wimpy. When I'm running the generator on a trip for the rooftop air, I'll run the fridge too; our generators have enough excess capacity to make that possible. If I'm not running the generator, I put the fridge into 12 volt mode. (Also note the 12 volt mode only works when the engine is running.)
1991 Airstream B190 - bought, 2005; sold, 2011; bought 2017
1995 Airstream Excella 30' trailer

WBCCI #13270, Washington, DC Unit
Wakeslayer
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Re: Monitor refrigerator temperature

Post by Wakeslayer »

As I have just come back from out shakedown trip, I have a 12v question about the fridge. We had some issues using the propane running and not finding a level spot the first night out. We simply pulled over in county park as it was 2am, in a terrible storm. I opted to use the 12v traveling home yesterday.
Anyway, after we got home last night, I decided to just leave that on overnight to verify it works properly. I see above that you say that doesn't work. However, I went out late this morning, and the fridge was still cold, and my battery meter showed my batteries half gone. Could someone have changed something?
Moving forward, I won't leave it on 12v other than driving.

Thank you
Mike
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Mike & Barbara
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skater
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Re: Monitor refrigerator temperature

Post by skater »

In mine, the 12 volt mode was hooked to accessory power in the engine only - it was off when the ignition was off (I checked this with a multimeter). It sounds like yours is wired differently, though. It's relatively easy to check with a meter, but I don't remember the details from mine to give you exact directions.
1991 Airstream B190 - bought, 2005; sold, 2011; bought 2017
1995 Airstream Excella 30' trailer

WBCCI #13270, Washington, DC Unit
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Planck
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Re: Monitor refrigerator temperature

Post by Planck »

On my 91 B190, there was a relay under the sofa that I believe was supposed to be wired into the ignition so that the 12v only worked when engine was running. Someone had by-passed this so that you could always run on 12v. Not sure about my 93, as have not used the 12v option. I use propane while traveling. Seems to work much better.

Good tips on the indoor outdoor thermometer. Gotta try that.
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