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Open Roads Forum  >  Tech Issues

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larry barnhart

wenatchee. wa usa

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Posted: 07/03/21 09:01pm Link  |  Quote  |  Print  |  Notify Moderator

Temperature was 115 for 3 days and the fridge stopped cooling but the freezer was working ok. Now after the big heat has gone the fridge is working again. Local rv store felt the issue was overheating and is going to see if the cooling unit needs to be replaced. This is something we have never experience before and have been rving since 1996. But never this hot. Dometic 12 ft. 2019 fifth but used one trip. Probably will get it tested . Anybody experienced this issue?

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Old-Biscuit

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Posted: 07/03/21 09:48pm Link  |  Quote  |  Print  |  Notify Moderator

115*F for 3 days
Freezer cooling but food compartment wasn't

I would say that was an obstructed cooling unit


BUT you went on to say that after the big wave passed the fridge starting cooling again (as in the food compartment got cold also?)

That suggest big lack of AIRFLOW/DRAFT across backside of fridge to remove the heat

Hot air has a hard time absorbing more heat so heat generated by fridge was not fully being removed in sufficient vloume to have enough cold coolant to absorb heat removed from freezer AND food compartment

FANS at top to PULL air in/push it out
Proper clearances across backside of fridge...less then 2"
Baffles to direct airflow if clearances are to wide


Test:
Unplug thermistor and let fridge run for 12 hrs
Freezer and food compartment get COLD....cooling unit is functioning

HEAT has to be removed..airflow/Draft


Is it time for your medication or mine?


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wa8yxm

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Posted: 07/04/21 08:09am Link  |  Quote  |  Print  |  Notify Moderator

The cooling unit is just fine or the freezer would thaw.

The unit simple reached the limit of cool.. The "Myth" (Global warming) is now at the point where absorption units can be overcome.

Thigs that might help
SHADE!!! This is the #1 way to help it Shade the area of the RV where the Fridge lies. Awning. Pop Up Shelter. anything to shade it.

Cleaning. At the top of the fridge. outside, is a "heat Exchanger" (The Radiator on your car or coils (Both condenser and evaporative) on an A/C are heat exchangers and this is not different in construction... Crud can build up under it.. Remove the top cap and blow down.. Keep the pressure low and volume high if you can (Do not want to bend fins) Open the lower access panel too before you do this.

A fan (or two) blowing UP through the heat exchanger.

NOTE it's a bit pricy but they sell a replacement "Cap" (for units that "Exhaust" Through theroof) Solar panel and solar powered fan to Suck it up


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dougrainer

Carrolton, Texas

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Posted: 07/04/21 08:16am Link  |  Quote  |  Print  |  Notify Moderator

wa8yxm wrote:

The cooling unit is just fine or the freezer would thaw.

The unit simple reached the limit of cool.. The "Myth" (Global warming) is now at the point where absorption units can be overcome.

Thigs that might help
SHADE!!! This is the #1 way to help it Shade the area of the RV where the Fridge lies. Awning. Pop Up Shelter. anything to shade it.

Cleaning. At the top of the fridge. outside, is a "heat Exchanger" (The Radiator on your car or coils (Both condenser and evaporative) on an A/C are heat exchangers and this is not different in construction... Crud can build up under it.. Remove the top cap and blow down.. Keep the pressure low and volume high if you can (Do not want to bend fins) Open the lower access panel too before you do this.

A fan (or two) blowing UP through the heat exchanger.

NOTE it's a bit pricy but they sell a replacement "Cap" (for units that "Exhaust" Through theroof) Solar panel and solar powered fan to Suck it up


IF THE COOLING UNIT WAS BLOCKED, THE FREEZER WILL STILL GET BELOW 32 DEGREES. IT WOULD NOT "THAW". Doug

dougrainer

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Posted: 07/04/21 08:21am Link  |  Quote  |  Print  |  Notify Moderator

Is the refer in a Slide room? When you say it started working again, THAT is a subjective opinion. What was the freezer temp? What was the actual lower refer temp? The temp for the lower is to be taken in a glass or water after 24 hours on MAX cold setting. Cooling units can be harmed 2 ways. Run OFF LEVEL for over 24 hours. OR, IF you have severe heat and inadequate or NO cooling air up the rear coils, you can "BAKE" a cooling unit which the result is the same as OFF LEVEL. Then you have to replace the Cooling Unit. Baking a cooling unit takes less than 24 hours if NO AIR FLOW AT ALL. If you had air flow but the 115 heat caused a flow problem, I will bet you are OK. Doug

2112

Texas

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Posted: 07/04/21 09:36am Link  |  Quote  |  Print  |  Notify Moderator

dougrainer wrote:

*snip*
Cooling units can be harmed 2 ways. Run OFF LEVEL for over 24 hours. OR …
*snip*
Not to hijack this thread but this is the first I have heard of a 24 hour limit. I have been under the impression short periods of off level accumulating over time would do it. Such as an hour off level per day several times is just as bad.

There are times during a travel day we'll stop for a break and I'm off level, usually nose high. I'll turn off the fridge while parked for an hour or so. Am I being a knucklehead for doing this?

Thanks


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mr_andyj

Georgia

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Posted: 07/04/21 10:01am Link  |  Quote  |  Print  |  Notify Moderator

2112. big Rush fan???
The fridge can run off-level up to 3 degrees side to side (fridge's side not trailers) and 6 front to back.
I have never heard the 24 hour limit either.
The damage occurs as soon as the unit is off-level and the liquid chemicals no longer are able to flow down the coils. The boiler gets starved for liquid and the stuff in the boiler (anti-corrosion chemical I believe) literally starts to cook. You can cook some and the fridge will still work, but eventually enough cooked particles build up and cooling suffers. I have heard the cooking described as dried concrete on the sides of the boiler. The boiler being the part that the flame heats.

A series of 48 30 minute sessions would add up to 24 hours. assuming the 24 hour thing is a real number then those 48 times would ruin it.
Almost everyone has run the fridge off level and done some damage, it is hard to not. Turing it off when you park helps, but how much damage will be done in the time it takes the boiler to cool off to the point it will not cook? I do not know this.

For OP.
It sound like your fridge was always working.
If it worked again when temps cooled off then it always worked. Fridges are not finiky, they work then they dont work, there is no reverse unless it is an air-flow issue or other issues as mentioned. We need more details to help u.

The freezer works because that is where it is mostly cooled. The fridge portion will be much more affected by outside temps. The insulation is a part of this. The box simply cannot put enough cold into the fridge to counter the heat coming across your thin insulation. This is why it will not work above a certain temp.

Things that help:
*Keeping the fridge side of camper in the shade (north side away from sun) so the entire side of the camper is not so hot as to keep the fridge hot.
*Using a fan to move air across the fins behind the fridge.
*Use a baffle to direct the moving air across the fins and not letting air bypass the fins and go around.
*More insulation for the fridge sides, top, bottom and door if possible.
*Keep the fins inside the fridge free so air moves across them, even using a battery fan to help move air.
* Don't open door.
*Keep fridge full so there is more "mass" of cold things, and not just massless air so when you do open door no cold escapes.
* ^ don't let a full fridge block the interior fins.
*Remove the shaded side fridge compartment outer door.
*make sure there are no blockages in the fridge compartment flu that would block the moving air.
*Check that your propane flame is high when you have cooling on high. It should be a small flame when on low and a high flame when on high. This applies to some fridges, and others might have just one size flame that turns on and off when needed. Older styles had an adjustable flame and no way to control the fridge inside temp other than a manual set flame that does not know what is going on inside the fridge.
*set fridge temp as low as possible at night so it has farther to go to warm up during the day. Keep fruits and veggies on top so they do not freeze just in case...

Lots of threads about this very issue, you can find more tips by searching the 1,000s of post on same topic

dougrainer

Carrolton, Texas

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Posted: 07/04/21 11:42am Link  |  Quote  |  Print  |  Notify Moderator

2112 wrote:

dougrainer wrote:

*snip*
Cooling units can be harmed 2 ways. Run OFF LEVEL for over 24 hours. OR …
*snip*
Not to hijack this thread but this is the first I have heard of a 24 hour limit. I have been under the impression short periods of off level accumulating over time would do it. Such as an hour off level per day several times is just as bad.

There are times during a travel day we'll stop for a break and I'm off level, usually nose high. I'll turn off the fridge while parked for an hour or so. Am I being a knucklehead for doing this?

Thanks


You are doing it correct. BUT, I state the 24 hours as what will probably destroy a Cooling unit to the point where it will not function correctly in higher temps. People run off level overnight and then they think OH OH. But then the refer seems to work correctly so they think level is a wives tale. BUT, that 24 hours has caused a small blockage, enough to degrade the best performance of the cooling unit. Over time all those times run off level accumilate the blockage until one day the lower refer just will not perform as it should and they think it just happened. Doug

PS, if you have total blockage of the rear outside convection air for 24 hours, IT WILL destroy the cooling unit. I had a customer have CG replace his rubber roof on his storm damaged 2 year old RV and the idiots installed the roof refer vent, BUT FAILED to cut out the rubber over the hole. First 24 hours on his trip the CU was baked and destroyed.

2112

Texas

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Posted: 07/04/21 11:46am Link  |  Quote  |  Print  |  Notify Moderator

mr_andyj wrote:

2112. big Rush fan???
Yep. 2112 was some of Neil's best work, RIP. Besides, all the world a stage was too long for a username

Quote:

A series of 48 30 minute sessions would add up to 24 hours. assuming the 24 hour thing is a real number then those 48 times would ruin it.
This is how I understood it. Thanks for the feedback

2112

Texas

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Posted: 07/04/21 12:01pm Link  |  Quote  |  Print  |  Notify Moderator

dougrainer wrote:

You are doing it correct.
Thank You Sir

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