Norcold fridge

My fridge (Norcold model N611) seems to not work as well while traveling.
It was nice and cold this morning after on all night (33?f fridge and 12?f freezer. Everything we put in it before hitting the road was already cold, But after being on the road about 7 hours the fridge was up to 45?f and coils were dripping wet (not icy like usual), freezer was 23?f.  Now that we've been sitting an hour & 1/2 the coils are icing up again.
It acted like this a few months ago but I figured it was due to heat (the sun was shining on that side all afternoon but today was opposite). That day it was in the mid 90's but today I don't think it got over 88. When it did this a few months ago I switched to electric thinking maybe the wind was effecting the flame but it made no difference.
The coach is a 3 year old C class.
Any thoughts?

Just checked, the freezer is now right about 0?f, fridge is gradually cooling down.
I wonder if the drain tube is positioned wrong and allowing warm air in. Maybe I'll try to find something to plug the drain hole in the little "gutter" under the coils while mobile - until I get home and do some proper troubleshooting.

Things to consider :

Flame out from wind during travel.

Is it in auto mode?


Air flow disruption during travel.

Yes, I switched it to auto mode while traveling - no help.

Right now, after stationary for the night (on propane) freezer is -14?f, fridge is mid 30's (varies a bit depending on distance from coils).

skydivemark said:

Yes, I switched it to auto mode while traveling - no help.

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When you switched to Auto mode, all that did was if/when you connect to shore power, it will automatically turn off the propane flame and turn on the electric then switch back to propane when you disconnect from shore power, so it won't help you while driving except if you run your generator.
I'm also thinking that your flame may be affected by the wind. The wind may be blowing out the flame and when you stop, it may automatically light again and start the cooling process all over.
I would go and buy a piece of sheet metal and place it somewhat in front of the lower burner tube and see if that changes things. DO NOT plug up the lower vent access door. You still need that for proper air circulation when stopped.

I suspect the problem is airflow (or lack thereof) while driving. I've seen that on my own rigs when the wind was at the wrong angle. If air can't get in the side vent and up/out the roof, cooling decreases or stops altogether. Since the normal flow is just convection, it doesn't take much to stop it. 

Air passing around and over the RV creates pressure at some places and suction (vacuum) at others.  If there is a vacuum along the intake side or increased pressure near the outlet vent, that's all it takes.  I've heard of cases where somebody added something on the roof, e.g. another a/c unit, and it altered the air flow enough to use the fridge problems.

Try adding a 12v fan to the cooling unit compartment (behind the fridge) and see if that helps.  You can put it on a thermostat (the ARP Fridge Defend has an excellent fan control  part of its protection). Or there are fan kits such as these:

https://www.amazon.com/Valterra-A10-2618VP-FridgeCool-Volt-Exhaust/dp/B002N5YDG2

https://www.amazon.com/dp/B077TJCL3F/

Yes Rene,gen is running (to keep house cool for wife & dogs).
It's weird it only seems to act up in warm weather. In colder months it doesn't give us any problems.
Been back on the road a few hours and it's hanging in there. But we have several hours before stopping for the night(s).

In colder months it doesn't give us any problems.

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Another clue that the problem is reduced air flow. The fridge needs far less air flow in colder weather.

Gary RV_Wizard said:

I suspect the problem is airflow (or lack thereof) while driving. I've seen that on my own rigs when the wind was at the wrong angle. If air can't get in the side vent and up/out the roof, cooling decreases or stops altogether. Since the normal flow is just convection, it doesn't take much to stop it. 

Air passing around and over the RV creates pressure at some places and suction (vacuum) at others.  If there is a vacuum along the intake side or increased pressure near the outlet vent, that's all it takes.  I've heard of cases where somebody added something on the roof, e.g. another a/c unit, and it altered the air flow enough to use the fridge problems.

Try adding a 12v fan to the cooling unit compartment (behind the fridge) and see if that helps.  You can put it on a thermostat (the ARP Fridge Defend has an excellent fan control  part of its protection). Or there are fan kits such as these:

https://www.amazon.com/Valterra-A10-2618VP-FridgeCool-Volt-Exhaust/dp/B002N5YDG2

https://www.amazon.com/dp/B077TJCL3F/

Click to expand...

Pretty good idea Gary. I hadn't  even thought of that. At first, when you mentioned airflow, all i thought of was the flame itself. The coils didn't even enter my thoughts. Since it acts the same on electric(auto) and propane It may be the issue. I think the biggest obstacle with a fan would getting the wires ran up to the vent.
  I just looked and the cover over the fridge vent looks to be fair size. I  wonder if it's  just some type of obstruction limiting airflow (leaves, pine needles, mud dobber). There are a lot of trees (and bugs) where we park at home. Maybe the campground people here will be kind enough to loan me a ladder to go up and take a look. It seemed to work fine until just a few months ago.
I will update when i know more.

I bet you are onto the solution here.  I don't think manufacturers take into account roof airflow....but for the fridge to work it needs good airflow from the bottom to the top.  Most issues I've see revolve around the factory install of the fridge not meeting the specs of the fridge manufacturer's install guidelines.....

-Chak

Haven't had a chance to seriously troubleshoot it yet but see  the skylight for the shower is right behind the fridge vent. It's fairly tall, (maybe 10-11 inches) so I wonder if that could be disrupting airflow. It has a crack and the replacement (which will get installed soon) is only 3-4 inches tall. I wonder if that will help.

It's all but impossible to guess air flow by eyeball - you need a wind tunnel to blow smoke over it at speed to see what really happens, no matter how obvious it may appear. A subtle change bump or dip several feet away can have unforeseeable effects.

Yes you're right. Being in aviation for over 40 years i certainly know air flow can be effected in ways that would surprise a lot of people.

Finally checked for obstructions, and did find a fair amount of pine needles & leaves in and under the upper fridge vent cover. Blew it all out with shop air.
Also replaced the shower skylight (was cracked) which is right behind the fridge vent. The old one was quite tall (atleast 10") and the new one is only a few inches tall and much smoother contour. I do wonder if the tall skylight effected the airflow out of the fridge vent.
We have a trip in a few weeks, so we'll see if these things helped.
I still like the idea of a vent fan but don't know how to run the power wire(s) up there. If anyone else has installed one of these fans please let me know how you routed the wire(s) up there, or did you install it somewhere other than on top where the air exits? (If it helps, I have a rubber roof).

Gary, I have seen that Valtera A-10 advertised. I was told db's are high and u can hear it from inside the rig. Any  opinion.

I just pulled a Norcold 2400. It had rwo fans mounted on the fridge about 2/3 of the way up and blowing up. Worked well for years until the fridge died. New GE  is setting just outside my door.

Ernie

Valterra uses "A-10" on numerous products (some are not even fans), so not sure which one you are looking at.  Maybe the A10-2618 or A10-2628?

The fan can be installed anywhere behind the fridge as long as it is blowing upwards toward the exit vent.  Above the lower air inlet is best, but not strictly necessary.  They have a thermostat, so probably don't run all the time, especially not at night when a fan hum is more likely to be noticeable (and bothersome).  I've not seen any complaints about Valterra fan noise here, but that doesn't prove much.
If you like, buy a mid-sized computer/electronics fan and a 12v thermostat and make your own. Computer fans are pretty much silent. Here's a fridge fan thermostat used with the Norcold factrory fans:
https://www.rvautoparts.com/618093-Norcold-Refrigerator-Cooling-Fan-Thermostat-Replacement-For_p_35157.html
Or, install an ARP Fridge Defend fridge boiler monitor that includes a fan control circuit. It substantially improves safety as well as providing fan management (thermostat based on actual boiler temperature).

My Dometic fridge was a useless paperweight for years. It would freeze stuff in the freezer section but never got below 45 deg F in the fridge section.  I did two things that really exceeded my expectations and gave me a fridge that works as well as a residential unit.  I needed my fridge to work as I am now living full time in my RV and I regret now doing the following years sooner!

I put 4 CPU cooling fans on my Dometic fridge roof vent.  A pair of two fans are wired to individual switches.  When I'm travelling or stationary in temps above 80 deg F, I run four fans.  In temps 60 to 80 deg F, I run one fan whether stationary or moving.  I used cheap $8 4 inch sleeve bearing fans that are rated for over 20,000 hours of use.  I put a lot of use on them this year and if they fail or make noise, I"ll replace them but that shouldn't be a for a long time.

Next modification that made a ton of difference.  SNIPTHETIP https://www.snip-the-tip.com/cgi-bin/articca.cgi  This replaces the worthless thermistor that doesn't maintain a consistent tip and doesn't require moving it up and down a cooling fin.  My temps are now rock steady as long as cooling fans are running in hot temps.  I no longer worry about my food going bad even when it is over 100 deg F outside!


Please try the snipthetip mod.  I'm not associated with the company in anyway just a very HAPPY customer.  As I'm typing this, my fridge shows 36.6 degrees on the upper level and  38.1 deg F on the lower section.  I have two digital thermostats that record temps and am impressed with these two mods.

Another mod is a circulating fan.  I used two small cooling fans attached to the fins that help airflow especially when the fridge is packed to the gills.  I got this kit from online and easy to find.

I used a cheaper quieter computer fan mounted in the chimney of my fridge connected in to the DC power connection screw terminal that powers the refrigerators logic board.  I used a thermal sensor clipped to the return tubes to turn it on and off in order to save power but you can wire it straight or add a manual switch.

The fan I used was IP56 rated for dusty environments like this one https://smile.amazon.com/Rosewill-Silent-Resistant-Splash-Proof-RAWP-141411

Another alternative is a solar powered roof vent cover like https://www.amazon.com/Camco-42162-Solar-Panel-Refrigerator/dp/B002OUF554

or you could roll your on and save a bundle of money with the above mentioned IP56 computer fan plus a small solar panel like: https://smile.amazon.com/gp/product/B079G65ZCW mounted to the top of your refrigerator vent.