What affects your evaporative fridge. and why?

[Kahoona]

This is conjecture and will only interest those of us that spend a lot of time wondering what sometimes makes our fridges so unpredictable. We replaced the works (?) on ours with a Amish unit and the change was night and day. It would hold 33f in the desert sun without batting an eye but now on the east coast it is showing 49f on an extremely humid day, thus the question.


I am wondering if high humidity reduces cooling in an evaporation fridge? I can't see that it would if the same flame goes up the same flue and the seals are tight but yet there it is.



Next question is does a frosted freezer keep the fridge from cooling? The way they work is that the freezer gets the cooling first (when starting a dometic that has been off you notice that the freezer gets cold before the fridge. The Thermostat is in the fridge and it determines when the flame stops. Shouldn't matter but it seems to.



Why do some people's evaporative fridges get warm while we are driving? Ours sometimes does but it cools right down when we stop. I can see a ton of reasons for that. Air gusts blowing air down the flue, The flow on the back getting reversed and not cooling the fins for instance.



What bothers your eveporative fridge and why? I don't want to hear about how you changed to a compressor powered fridge, just the quixotic evap fridge please.

[TonyMac]

I put fans on my interior fins. They circulate the air so well that I can go from a setting of 6 to a setting of 5 and still get 12 degrees in the freezer and 35 in the fridge.

[NXR]

Originally Posted by Kahoona

I am wondering if high humidity reduces cooling in an evaporation fridge? I can't see that it would if the same flame goes up the same flue and the seals are tight but yet there it is.

Humidity does not seem to affect our Norcold 1210 cooling at all. Our fridge is in a slide.

Next question is does a frosted freezer keep the fridge from cooling?

Not on ours nor does it affect the freezer temps. I keep a wireless temp sensor in one freezer compartment and the fridge so, yes, I am certain.

Why do some people's evaporative fridges get warm while we are driving? Ours sometimes does but it cools right down when we stop.

Ours used to do that. The fridge and freezer would go up maybe five degrees while driving. As soon as we stopped at a rest area down the temps came.

The factory seriously messed up the installation and the dealer made some partial fixes. We went back to the factory and the fridge was pulled. A fellow from Norcold supervised the reinstallation and the factory had their fridge installers attend so they could see what their shortcuts were doing.

Now that the fridge in a slide is installed completely in accordance with the manual it actually gets cooler when driving. The freezer can be around 3 or 4 degrees when we start out and will go down to -1 or -2. The fridge will go from 36-37 down to 32-33.

If you have a roof vent, which we do not, I'd think your problem is that air is being pushed into the roof vent and affecting the upward air flow.

I did purchase an ARP Fridge Defend with the four extra fans but have not fully installed it. The ARP device is installed except for the part that actually monitors the boiler tube temperature.

So all it's doing is controlling the extra fans.

I put their two small (maybe 2") interior fans inside on the fridge ceiling and they get pointed at the cooling fins. The fans take warmer air at the top of the fridge and blows it against the fins to circulate air in the fridge and also to keep the fins frost-free. Those interior fans definitely help the fridge cool down faster after food is added. Previously, adding six water bottles as fast as I could would push the fridge to 42 to 45. Now adding a dozen may affect the temperature one degree. (I keep the wireless temp sensor on the top shelf.)

I installed one of the ARP exterior fans on the lower fridge vent door (the air inlet) to pull air in and push it up. It turns on and off with the cooling unit. I now have a very nice breeze coming out the top vent whereas before it was just a very light breeze.

With the temps in the high 80's or low 90's and direct afternoon sun on the slide with the fridge I now need to run the fridge at a setting of "2", which is the second warmest setting, to keep the fridge above freezing.

So, for us, it was all about proper venting on the outside and air circulation on the inside.

Ray

[Old-Biscuit]

Originally Posted by Kahoona

This is conjecture and will only interest those of us that spend a lot of time wondering what sometimes makes our fridges so unpredictable. We replaced the works (?) on ours with a Amish unit and the change was night and day. It would hold 33f in the desert sun without batting an eye but now on the east coast it is showing 49f on an extremely humid day, thus the question.


I am wondering if high humidity reduces cooling in an evaporation fridge? I can't see that it would if the same flame goes up the same flue and the seals are tight but yet there it is.
YES it can affect 'cooling'
Doesn't affect the flame as much as the ability to Condense....draft/airflow goes across the Condenser fins to cool the hot ammonia vapor into warm ammonia liquid. More heat absorbed from condenser the more ammonia vapor turns into liquid the more liquid the more absorption of heat from freezer and food compartments
Humid air has water which is slower to absorb heat then air due to mass


Next question is does a frosted freezer keep the fridge from cooling? The way they work is that the freezer gets the cooling first (when starting a dometic that has been off you notice that the freezer gets cold before the fridge. The Thermostat is in the fridge and it determines when the flame stops. Shouldn't matter but it seems to.

YES Ice/frost can inhibit heat transfer/absorption. Ice is an insulator (igloo)
Thermistor is temp sensor in food compartment which thermostat uses to control heat cycles for cooling. Freezer is 1st in process so that food compartment temp is what needs to be controlled


Why do some people's evaporative fridges get warm while we are driving? Ours sometimes does but it cools right down when we stop. I can see a ton of reasons for that. Air gusts blowing air down the flue, The flow on the back getting reversed and not cooling the fins for instance.

Air currents alongside of RV can inhibit/disrupt Draft. Lack of good draft...less condenser heat removed. And/or flame gets pushed away from electrode...loss of Flame Proving..no reignition/fridge temps rise


What bothers your eveporative fridge and why? I don't want to hear about how you changed to a compressor powered fridge, just the quixotic evap fridge please.

Many times RV absorption fridge cooling issues are directly due to RV MFG Installation....lack of proper installation in accordance with required Clearances, draft and sealing

Some issues are owners fault....Off level Ops, Window shopping for food, placing HOT foods in fridge, lack of routine housekeeping (cleaning/maintenance)

Our Fridge was built during the 'cutting corners' time frame and YET it has preformed flawlessly since Sept 2006.
RV MFG correctly installed it per Fridge MFG requirements, I routinely clean/maintain it....haven't had to replace any component yet.

[Kahoona]

Originally Posted by NXR

Humidity does not seem to affect our Norcold 1210 cooling at all. Our fridge is in a slide.


I don't think it bothers ours either except to drip off of the fine when we aren't running a fan inside the fridge.




Not on ours nor does it affect the freezer temps. I keep a wireless temp sensor in one freezer compartment and the fridge so, yes, I am certain.



Ours used to do that. The fridge and freezer would go up maybe five degrees while driving. As soon as we stopped at a rest area down the temps came.

The factory seriously messed up the installation and the dealer made some partial fixes. We went back to the factory and the fridge was pulled. A fellow from Norcold supervised the reinstallation and the factory had their fridge installers attend so they could see what their shortcuts were doing.


I agree with that. Ours is in a slide also but the compartment, 'specially in the upper area and the sealing around the sides was terrible. Ours was made in the last year National made campers so they probably didn't care. I did a pit of work to improve that area. Still more to do though.


Now that the fridge in a slide is installed completely in accordance with the manual it actually gets cooler when driving. The freezer can be around 3 or 4 degrees when we start out and will go down to -1 or -2. The fridge will go from 36-37 down to 32-33.

If you have a roof vent, which we do not, I'd think your problem is that air is being pushed into the roof vent and affecting the upward air flow.

I did purchase an ARP Fridge Defend with the four extra fans but have not fully installed it. The ARP device is installed except for the part that actually monitors the boiler tube temperature.



You would get a kick out of our fans. We do have 2 that blow upward on the cooling fins. Those really are the most effective but we also picked up a couple of very large computer cans with LED lights that change color with speed. They actually blow straight out of the upper grille and make it easy to tell when we are "on the fans".


So all it's doing is controlling the extra fans.

I put their two small (maybe 2") interior fans inside on the fridge ceiling and they get pointed at the cooling fins. The fans take warmer air at the top of the fridge and blows it against the fins to circulate air in the fridge and also to keep the fins frost-free. Those interior fans definitely help the fridge cool down faster after food is added. Previously, adding six water bottles as fast as I could would push the fridge to 42 to 45. Now adding a dozen may affect the temperature one degree. (I keep the wireless temp sensor on the top shelf.)

I installed one of the ARP exterior fans on the lower fridge vent door (the air inlet) to pull air in and push it up. It turns on and off with the cooling unit. I now have a very nice breeze coming out the top vent whereas before it was just a very light breeze.

With the temps in the high 80's or low 90's and direct afternoon sun on the slide with the fridge I now need to run the fridge at a setting of "2", which is the second warmest setting, to keep the fridge above freezing.

So, for us, it was all about proper venting on the outside and air circulation on the inside.

Ray

123

[Kahoona]

Anybody else have any odd behavior with their evep fridge?

[NXR]

Originally Posted by Kahoona

Anybody else have any odd behavior with their evep fridge?

Apparently ours behaves oddly because it works really well.

Ray

[Kahoona]

Originally Posted by NXR

Apparently ours behaves oddly because it works really well.

Ray

[Kahoona]

I suspect that one factor is weather it spends most of it's time connected to shore power and set up in a campground or weather it is traveling and staying at Walleys, boondocking or national no hookup places. The one in our 60's Yellowstone which was shared between at least eight people, lived at South Jersey campgrounds for about 10 years between moves. It was turned off with the door open when no one was there. It was level. Shore power only. It never missed a beat over the 50 years it was used.

Another factor is age. The older the better as far as I know. The one in our 2001 Motorhome never had any problems at all no matter what we did. They were simpler. The bells whistles and electronics don't take much to go bad.


As part of the fun we are comparing our big 4 door dometic with Amish works in frosted and defrosted to see if it matters to the conditions above. It will take another week or so until we know. We have done the defrost and now need to compare.

[Kahoona]

Originally Posted by Kahoona

This is conjecture and will only interest those of us that spend a lot of time wondering what sometimes makes our fridges so unpredictable. We replaced the works (?) on ours with a Amish unit and the change was night and day. It would hold 33f in the desert sun without batting an eye but now on the east coast it is showing 49f on an extremely humid day, thus the question.


I am wondering if high humidity reduces cooling in an evaporation fridge? I can't see that it would if the same flame goes up the same flue and the seals are tight but yet there it is.



No, Humidity does not reduce cooling.


Next question is does a frosted freezer keep the fridge from cooling? The way they work is that the freezer gets the cooling first (when starting a dometic that has been off you notice that the freezer gets cold before the fridge. The Thermostat is in the fridge and it determines when the flame stops. Shouldn't matter but it seems to.


Yes, a covering of as little as a quarter of an inch of frost/ice on the back panel causes poor performance in fridge and only slight but noticeable in freezer.


Why do some people's evaporative fridges get warm while we are driving? Ours sometimes does but it cools right down when we stop. I can see a ton of reasons for that. Air gusts blowing air down the flue, The flow on the back getting reversed and not cooling the fins for instance.

Again the frost makes the difference. Slight problem only when frost free and larger when frosted.

What bothers your explorative fridge and why? I don't want to hear about how you changed to a compressor powered fridge, just the quixotic evap fridge please.

Thanks for putting up with my rambling. I had this perfect set up to test the effects of frost and decided to have fun with it.