3-way fridge use

[alwechs]

I have another fridge-related question. I am a new class B owner, and this has a (currently inoperable) 3-way fridge. While I contemplate replacing it, it strikes me that these fridges may not be the most convenient if one is driving and stopping a lot. If I understand how they operate, the fridge runs off the alternator when I'm driving. But once I stop, I would need to open the gas line and switch it to propane, is that right? Then I have to remember to switch it back and turn off the gas line when I start up again. This seems rather inconvenient to me. Can anyone speak to how well these fridges keep cool? Like if I park the van for a half-day hike, will it still be cool when I come back or would I need to turn on the propane? What about if I stop for a two-hour swim somewhere?

Would love to hear some thoughts on how these small Class B fridges perform and the complications of switching from one power source to another. It sounds like house batteries aren't an option (unless maybe you have solar?) due to the amount of power it draws. Thanks.

[Rlum]

Originally Posted by alwechs

I have another fridge-related question. I am a new class B owner, and this has a (currently inoperable) 3-way fridge. While I contemplate replacing it, it strikes me that these fridges may not be the most convenient if one is driving and stopping a lot. If I understand how they operate, the fridge runs off the alternator when I'm driving. But once I stop, I would need to open the gas line and switch it to propane, is that right? Then I have to remember to switch it back and turn off the gas line when I start up again. This seems rather inconvenient to me. Can anyone speak to how well these fridges keep cool? Like if I park the van for a half-day hike, will it still be cool when I come back or would I need to turn on the propane? What about if I stop for a two-hour swim somewhere?

Would love to hear some thoughts on how these small Class B fridges perform and the complications of switching from one power source to another. It sounds like house batteries aren't an option (unless maybe you have solar?) due to the amount of power it draws. Thanks.

Three ways have been around a long time. They work but have limitations. Van should be level for them to work best. They work by chemical reactions. Works best on propane than ac and finally dc. If you are driving and traveling lots, your best bet is a compressor refrigerator run on dc. Only issue if you have small battery bank. These refrigerators need about 2-3amps per hour. So you can see after 24 hours, your batteries will require recharging unless you have a large bank.

[hbn7hj]

You need a wireless fridge thermometer and then make your own use decisions.
https://www.amazon.com/AcuRite-Refri.../dp/B004QJVU78

As for the repair you need to do that yourself. First you need to determine if the cooling unit is working. You do that by providing AC to the AC heating element without going through the control board. If the AC element heats and the fridge does not cool then the fridge is junk. If it does cool then you have control board problems that can be dealt with.

[tbroad]

We have found the 3-way fridge gives us the best of all worlds, even though lighting the propane option can often be a bit frustrating.
* 120v AC when prepping to depart on a trip or visiting family/friends when I can run a long extension cord. It only draws ~120 watts, so we don't use the honking thick and short 30-amp monster -- we carry a 100-ft 16-gauge cord that works fine and gives us flexibility where we park.
* 12v (referred to as "running off the alternator," though technically its running off the house battery and the alternator is charging that battery at the same time) is great for driving. Doesn't cool as well as AC, but it works fine. The problem, as you noted, is when you stop driving. A 1-hour shopping trip or lunch stop? No problem, leave it on 12v. These fridges typically draw ~10 amps from the house battery, so you so the math. We have a 100w solar panel, which on a typical sunny day with sun-angle might put out 5-6 amps, so the time can be extended.
* Propane when camping -- unless, of course, one goes to a "resort" site with power, in which case run on AC.

In short, a half-day hike would probably be pushing the limits of battery, unless you have a large capacity bank. Get a wireless refrigerator/freezer thermometer (as already suggested) to gather data on your fridge.

[hbn7hj]

Mentioned it before but if you put a relay in the DC heater line triggered by the alternator output inadvertent battery drain is no longer a problem. Works great for gas stops.

[eric1514]

Originally Posted by hbn7hj

Mentioned it before but if you put a relay in the DC heater line triggered by the alternator output inadvertent battery drain is no longer a problem. Works great for gas stops.

I did just that because of you and a post you made several years ago. Thanks. I learned some stuff about relays and wiring because of you.

Here's the link

https://www.classbforum.com/forums/f...gain-5596.html

[Lou]

We once forgot to switch from battery to propane during a prolonged lunch break (picnic, swim) and that emptied the house battery. So now, each morning, we remove two ice packs from freezer, put in fridge and make sure mini battery fan is still able to move air around. When we are ready to travel we turn the fridge off.

While stopped for lunch we put propane on. Arriving at camp we put icepacks back in freezer and they are ready for next day (also keep one extra). This works for us (checked with thermometre).
We use electric at home (getting ready) and if campground has hookups. We mostly wander, travel in the Pacific Northwest (home BC) not in hot desert country.

[GeorgeRa]

Operating not leveled absorption fridges will fail at some point. Each time a not levelled fridge operates it adds to failure, it is accumulative.

Unfortunately, being leveled definition is vague, some say: if you feel comfortable, or pencil doesn’t roll, +/- 3 degree in for and aft, or don’t worry, or switch to compressor.

The primary result of operating not leveled fridge is overheated boiler. There is a company which adds a safety loop and turns off heating if boiler overheats. I was ready to install device like that on my last absorption fridge but the RV got sold. https://www.arprv.com/ I think there is another company with a similar product. For folks with experience a simple thermo sensor switch on the boiler could be added.

My new camper van has compressor 85l fridge with 230Ah battery and 300W of solar, works great.

[RAA357]

I have a Dometic 3 way powered refrigerator that works just great.
on 12vdc it gets down to 30 degrees, shore power gets down to 29 and gas gets down to 28 degrees. I slid the little thermostat adjustment slide on the cooling fins all the way to top and on the 3 fin from the right hand side to get those temps and the outside temp adjustment to #5.

I also installed a 12vdc computer fan that blow air on the circulation coils of the refrigerator. A fan will also go a long way toward helping your fridge stay cool. Air circulation is a major factor in cooling efficiency.

[hbn7hj]

Originally Posted by eric1514

I did just that because of you and a post you made several years ago. Thanks. I learned some stuff about relays and wiring because of you.

You matched me and raised me one. My senile mind could use the LED.

The level datum for 3 way fridge is the floor of the freezer. Match that to your counter tops or a glued on bulls eye level and all will be well.

If the fridge is cooling it is OK. I have been running the ARP device for years. It has warned me of a failing AC heater and a high resistance fuse on the DC heater power. Lower heater power results in an overtemp boiler. Don’t ask to explain why.

[GeorgeRa]

Originally Posted by hbn7hj

.................
If the fridge is cooling it is OK. I have been running the ARP device for years. It has warned me of a failing AC heater and a high resistance fuse on the DC heater power. Lower heater power results in an overtemp boiler. Don’t ask to explain why.

Did ARP turned off the fridge if boiler exceeded set temperature?

[hbn7hj]

Originally Posted by GeorgeRa

Did ARP turned off the fridge if boiler exceeded set temperature?

Yes. I put a light on the dash to tell me when the fridge went off. The circuitry for that was complex as you don’t want the light to come on with the ignition off.

Without that warning I would have never known things weren’t right. It also shut off the boiler when the ammonia leaked out rather than sit there and cook.

I have never had it turn off when off level, even when stopped for construction on a 6 degree slope. Maybe I wasn’t stopped long enough.

I also use the ARP to control a fan on the condenser.

[GeorgeRa]

Originally Posted by hbn7hj

Yes. I put a light on the dash to tell me when the fridge went off. The circuitry for that was complex as you don’t want the light to come on with the ignition off.

Without that warning I would have never known things weren’t right. It also shut off the boiler when the ammonia leaked out rather than sit there and cook.

I never had it turn off when off level, even when stopped for construction on a 6 degree slope. Maybe I wasn’t stopped long enough.

Would you recommend using this device?

[hbn7hj]

Originally Posted by GeorgeRa

Would you recommend using this device?

Not sure. It is very difficult to install in a class B. The unit must be removed and it is still difficult. It has never alarmed on my Roadtrek. It has cut the heater off several times on my C. Weak AC heater, weak DC heater, failed cooling unit, but never for off level. I pay attention to the level.

It does power the fan and turns it off when the condensing fluid is below 130F. It does do what the manual says it will do so I guess that is a good recommendation. I still use it and make sure it is on. The fan they provide has yet to fail. All computer fans I put back there have failed.

The plastic case burns like gasoline. I failed to tighten a propane fitting and got a fire back there. Got it put out with a Halon extinguisher. The Dometic control box case melted. The ARP case was the only thing burning when the propane was turned off. Dometic picked the right plastic for it’s case, ARP did not. I never told them about that.