Altitude Effects on Fridge?

[adamis]

I have been camping in northern California for the last two years with my 2001 Bigfoot camper. I have a Dometic fridge that I assume is from the same time frame (I bought the camper about two years ago).

On a previous Lance camper I noticed that the coils on the back of the fridge would get very cold to the touch. On my current camper however the coils are only moderately cold to the touch.

Performance wise the fridge has mostly worked fine, I would see internal fridge temps of 32 degrees and the freezer would freeze well. It would take at least a full day to chill down once turned on and would rise in temp a bit when stocked with food.

For the last year all of my trips have been at lower elevations. This week I've been on a trip to Tahoe (6500ft) and I've noticed the fridge struggling to stay cold, hovering in the 40s (freezer is still fine). I thought it was because we were just in and out of it a lot but this morning I checked it first thing in the morning and it was reading 40 degrees when it would usually be 32 degree. It was 50 degrees last night and day time temps are in the mid to high 70s.

My question is whether it's possible that the fridge could be low on the ammonia gas just enough that it works okay in lower elevations but at higher elevations it's not working quite as well. I am leaning this direction just because the coils on my fridge are not cold like they were with my other camper.

Any thoughts?

[SidecarFlip]

Never had one rust out. The Lance I sold this spring was 11 years old and the tubing was fine.

[SidecarFlip]

Old-Biscuit wrote:

SidecarFlip wrote:
First off, Ammonia fridges don't slowly die. they die from the ammonia solution leaking out from corroded piping and if they 'spring a leak', you'll know right away because one, you will smell it and two, you'll see it. The solution as it leaks will leave a yellow stain (usually around the lower part of the boiler, which is the sulfur in the refrigerant solution. That is a rare thing.

Ammonia fridges CAN die a slow death....without ever leaking

Off level operation disrupts the gravity flow of coolant, that causes overheating issues, sodium chromate crystallizes (anti-rust inhibitor---yellowish residue when a leak occurs).
The crystals plate out on inside of tubing causing more overheating, more plating etc.
Damage is accumulative......slowly dying cooling unit

20 minutes off level can cause this......

I forgot about that (congestive heart failure), but then I'm always level (when stationary) within 1/2 bubble. Not something that concerns me.

[Photomike]

Old-Biscuit wrote:

SidecarFlip wrote:
First off, Ammonia fridges don't slowly die. they die from the ammonia solution leaking out from corroded piping and if they 'spring a leak', you'll know right away because one, you will smell it and two, you'll see it. The solution as it leaks will leave a yellow stain (usually around the lower part of the boiler, which is the sulfur in the refrigerant solution. That is a rare thing.

Ammonia fridges CAN die a slow death....without ever leaking

Off level operation disrupts the gravity flow of coolant, that causes overheating issues, sodium chromate crystallizes (anti-rust inhibitor---yellowish residue when a leak occurs).
The crystals plate out on inside of tubing causing more overheating, more plating etc.
Damage is accumulative......slowly dying cooling unit

20 minutes off level can cause this......

You beat me to it...... in fact that is what happened to mine. Over time the piping got clogged and reduced the effectiveness. That is one of the reasons that you buy a new cooling unit, the other is for rusting out and the ammonia leaking.

[Old-Biscuit]

SidecarFlip wrote:
First off, Ammonia fridges don't slowly die. they die from the ammonia solution leaking out from corroded piping and if they 'spring a leak', you'll know right away because one, you will smell it and two, you'll see it. The solution as it leaks will leave a yellow stain (usually around the lower part of the boiler, which is the sulfur in the refrigerant solution. That is a rare thing.

Ammonia fridges CAN die a slow death....without ever leaking

Off level operation disrupts the gravity flow of coolant, that causes overheating issues, sodium chromate crystallizes (anti-rust inhibitor---yellowish residue when a leak occurs).
The crystals plate out on inside of tubing causing more overheating, more plating etc.
Damage is accumulative......slowly dying cooling unit

20 minutes off level can cause this......

[SidecarFlip]

First off, Ammonia fridges don't slowly die. they die from the ammonia solution leaking out from corroded piping and if they 'spring a leak', you'll know right away because one, you will smell it and two, you'll see it. The solution as it leaks will leave a yellow stain (usually around the lower part of the boiler, which is the sulfur in the refrigerant solution. That is a rare thing.

Just listen to Mr. Biscuit he knows.

Air flow across the upper evaporator (on the backside of the fridge) always improves efficiency. The unit has to get rid of heat before it can cool and that applies to all fridges, not just an ammonia fridge. Airflow, proper insulation and keeping the door closed and using a remote sensing thermometer (instead of opening the door all the time to check the interior temperature) all work toward keeping the fridge cold.

Ammonia fridges don't recover as quickly as a compressor fridge recovers, Keep the door closed as much as possible.

Interior temps below 42 are fine for food. They are not impacted by changes in elevation at all. They are impacted by external heat like the sun shining on the fridge side of the camper, especially with no additional induced air flow.

People tend to ignore the fridge until it fails and failure (besides the control board) is usually caused by a fouled from dirt or bug poop burner orfice and/or a sooted up boiler flue caused from improper maintenance. All ammonia fridge's that use multi method heating of the boilers (propane / 110v / 12 volt) have a removable flue baffle in the boiler accessed at the top outlet (of the boiler). It's removable and cleanable. I bet 99% of campers don't even know it's there, but then 99% of campers never bother to read the owners manual until an appliance don't work correctly and then they may (or may not) read it. Why bother when you can get online and ask and someone will answer. Everything you need to know is in the manual that came with the appliance. Reading comprehension is poor today....lol

Mr. Biscuit knows. Just abide by his comments.

[Old-Biscuit]

Geewizard wrote:

Old-Biscuit wrote:
Cooling unit is SEALED and under high pressure (300# Plus)
NO..altitude does not affect fridge as in 'low ammonia' etc.

Low ammonia means LEAK and then there is NO ammonia/hydrogen gas etc


Altitude does have affect on fridge cooling......thinner air----fuel rich...cooler flame for heating

What's a person to do?
Well there isn't a 'high altitude kit', there isn't an 'air shutter' to adjust air ....fridge has fixed air inlet based on propane gas flow/pressure.

Need to check that burner flame is strong,steady, blue.
If yellowish/lazy then need to get more air to burner.

Remove lower vent cover and see if flame improves.

I disagree. There is, more or less, a "high altitude kit" for Dometic refrigerators. It's called a burner orifice. They are easy to remove and replace as needed for higher altitude operation.

Dometic nor Norcold or even Atwood 'market' a high altitude kit.
(Except for a Dometic-Serval)

Correct changing orifice sizing is how you can change the fuel delivery.

But do you use a #58, a #43 or maybe a #39 :H

Conversion charts don't even go low enough.....large fridge uses a 2200 btu/hr. (18 orifice) Charts start at 10,000 btu.

Suburban does market a high altitude kit for their 6 gal and larger size water heaters.....they all use the same 12,000 btu burner.
The high altitude kit is the orifice they use in their 3 gal/8000 btu burner

So yes..you can change out orifices IF you know which one to use.

[Geewizard]

Old-Biscuit wrote:
Cooling unit is SEALED and under high pressure (300# Plus)
NO..altitude does not affect fridge as in 'low ammonia' etc.

Low ammonia means LEAK and then there is NO ammonia/hydrogen gas etc


Altitude does have affect on fridge cooling......thinner air----fuel rich...cooler flame for heating

What's a person to do?
Well there isn't a 'high altitude kit', there isn't an 'air shutter' to adjust air ....fridge has fixed air inlet based on propane gas flow/pressure.

Need to check that burner flame is strong,steady, blue.
If yellowish/lazy then need to get more air to burner.

Remove lower vent cover and see if flame improves.

I disagree. There is, more or less, a "high altitude kit" for Dometic refrigerators. It's called a burner orifice. They are easy to remove and replace as needed for higher altitude operation.

[jimh406]

I have a Dometic. It works fine at Yellowstone at about 8000 ft on propane. We've only had hookups one time.

[Kayteg1]

Fridge airator
When you have freezer working well and refrigerator on warm side, you need inside fan.
Here is one with charcoal filter, but battery operated. Don't see those with 12V

[portscanner]

You might need to add a fan to the rear coils of the the refrigerator. The installation of the refrigerator on some RV's do not provide for proper airflow across the rear coils for the most efficient operation of the refrigerator. I had to install a fan on all three of my RV's.

You can
- buy a new roof vent for the refrigerator that has a solar powered fan (however it does not work in the shade or at night - on the other hand there is no electrical wiring involved in the install)
- Buy a kit that contains all the parts for a thermostatic controlled 12v fan
- build your own. You will need an old fan out of a computer, a thermostat from Amazon (the one I selected was $14), a fuse holder and some wire.

[Photomike]

There could be many factors that is effecting it:

1) At altitude it could be cooler at night allowing it to catch up / stay cooler
2) Could have more wind to cool down the back of the unit at altitude
3) Parking in the shade at one place and not at the other
4) Different use pattern (doors open more when down lower)
5) More or less food

It could also be that the unit is slowly dying and it is not able to cool as well now as it could before.

With the fridge in my TCer I was able to see over the years that it was having a harder time cooling till one day I could not get it to cool at all. Replaced the cooling unit and it was good again.

With the class C I have now (a lot newer of a fridge) I can see how this one outperforms the one in the TCer. On the class C if I plug it in the freezer feels cold in about an hour, on the TCer would take 12 hours on the best day. The fridge is still not that much faster in cooling but it does seems to keep up better once cold.

[adamis]

Thanks for the comments so far. I have it running on propane. It seems that my setup is working normally. Maybe we just had it a bit overloaded and it's struggled to catch up. I think I'll look into adding a fan to the back to get some more airflow.

[Old-Biscuit]

stickdog wrote:
We're at 8,000 ft and the fridge is working fine running on electric. Dometic 2852 set on 2 shady side of the trailer freezer 0-5 fridge 39-42. Days 70-80 nights low 30s to low 40s. Worked as well in AZ but had to set on 3.

It should you are on 'electric'
Altitude has no affect.

Propane....altitude CAN effect flame temp

[stickdog]

We're at 8,000 ft and the fridge is working fine running on electric. Dometic 2852 set on 2 shady side of the trailer freezer 0-5 fridge 39-42. Days 70-80 nights low 30s to low 40s. Worked as well in AZ but had to set on 3.