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Topic: Norcold Fridge Question

Posted By: FreshAir on 12/12/07 05:56pm

Does the 12 cu. ft 4 door Norcold Fridge have a feature that allows it to operate in cold temps. below 30F like the Dometics "LAC, low ambient feature" does? If it does, where is the control switch that activates it? Is it automatic? Asking for a friend and don't remember the model. It's in an 03/04 Dolphin, Norcold 12 cf 4 door.
Thank's, Pat


Posted By: gmachine on 12/12/07 06:50pm

Service manual avail. here. Helped us a lot.
http://www.bryantrv.com/docs.html
Good Luck, Jim


Bering MD23(Cummins ISB)w/60" flattop Kenworth sleeper & 2005 Excel 35MKO Limited, 2006 Scion XA.


Posted By: dougrainer on 12/13/07 06:21am

Norcolds (last 10 years) do not have that feature. But, that LAC is not meant just for cold weather operation. What it does, is, it leaves the interior lite on all the time and that heat from the bulb keeps items like lettuce and produce from icing or freezing up IF the interior gets to about 32 degrees. Obviously this happens in colder outside ambient temps, but the solution is to turn down the T stat. If you have an Auto T stat Dometic, then the LAC is used. Norcold does NOT build a Auto Tstat model and all the Norcolds have adjustable Tstats for RV's. The outside temp (less than 40 degrees) means that the refer does not have to overcome the problem of Hot ambient causing it to work harder, hence items will get colder easier and faster. Doug


Posted By: Amberbunny on 12/12/07 07:45pm

Wow, I never really thought much about possibility of a fridge not working in cold weather. Read about spoiling food in the midwest where the power is out. Then I thought to myself . . .hello, its cold outside. Move the food to the porch. Yes I know lettuce won't freeze all that well but most food will do just fine and hopefully it won't attract bears, which is possible. But I never realized a fridge wouldn't work if it were too cold outside. I guessed if it was 50 odd degrees in the RV all was fine. Learn something new everyday.


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Posted By: FreshAir on 12/13/07 10:03am

dougrainer wrote:

Norcold does NOT build a Auto Tstat model and all the Norcolds have adjustable Tstats for RV's. The outside temp (less than 40 degrees) means that the refer does not have to overcome the problem of Hot ambient causing it to work harder, hence items will get colder easier and faster. Doug


Doug, my friend with the Norcold said his fridge quit keeping items cold when the outside temps started really geting cold. Are you saying there is nothing he needs to do as the Norcold is fully automatic regardless of the outside ambient temps? If so, he may have a problem.

Thank's everyone.


Posted By: dougrainer on 12/13/07 11:44am

Yes, he has a problem. Outside ambient should have no affect on the cooling and operation of the refer. If he is on LP and he is having a LP regulator problem in low temps, then it would be affected on LP, but on 110, he should have no problem.Doug


Posted By: Chris Bryant on 12/13/07 12:05pm

I disagree, Doug. If it's very cold out, the lower portion of the refrigerator will maintain 35-40° without the cooling unit running, because on that model the only temperature sensing is in the fresh food compartment.
Because the cooling unit isn't running, the freezer temperature will rise.
About the only cure is to either run it very cold (which will cause the fresh food to freeze), or add heat to the lower compartment, which is what Dometic does on their models with the LAT switch.


-- Chris Bryant
My RV Service Blog
The RV.net Blog


Posted By: dougrainer on 12/13/07 02:18pm

Chris Bryant wrote:

I disagree, Doug. If it's very cold out, the lower portion of the refrigerator will maintain 35-40° without the cooling unit running, because on that model the only temperature sensing is in the fresh food compartment.
Because the cooling unit isn't running, the freezer temperature will rise.
About the only cure is to either run it very cold (which will cause the fresh food to freeze), or add heat to the lower compartment, which is what Dometic does on their models with the LAT switch.


Well Chris, HOW cold does it have to be???? I doubt you could continue in sub 0 to 20 degree weather without the RV freezing up regardless of precautions. BUT, I HAVE used motorhomes in Colorado and New Mexico in 10 to 20 degree weather (Ski trips) and a LOT of my customers do also and I have never had a complaint of the freezer not cooling and the refer getting too cold even in my RV. WHY would the refer maintain a colder temp in VERY cold weather, but the freezer would not??? The box is insulated and the contents are not really affected by the outside temp. Please list your reasons for your answer. Doug


Posted By: Chris Bryant on 12/13/07 03:24pm

I disagree that the box is not affected by the outside temperature- even though it is insulated. The insulation in these boxes is far from perfect. There are a bunch of variables here- added insulation around the box, location of heating vents, etc.
I explained the why in the post above- this is a fairly common occurrence- I've heard of it often, which is why Dometic put the LAT switch in on their high end models (not the auto temp models, but the fully adjustable ones, the 3X series and NDR series).
We used to block off the outside vent in very cold weather to keep from freezing the fresh food while keeping the freezer at zero.

I really don't want to get in to a p*****g match here, I just want to point out that it does happen, and from my experience, the unit is not bad, and will work fine once the weather warms up.

* This post was edited 12/13/07 03:53pm by Chris Bryant *


Posted By: Troubleshooter on 12/13/07 03:26pm

While I won't try to go into the theory of why it happens, I personally know of a case where it has happened.
While moving from one abode to another, we put our freezer full of food in a unheated outside storage shed. Winter set in, and I didn't give it a second thought about the cold weather. About a week or so later the DW wanted me to get something out of the freezer, and when I opened it, you don't want to know what odors I was hit with. The temperature of the shed was about 10°F, whereas the internal temperature of the freezer was about 45°F.
Yes, it was plugged in, and there had been no power failure.
A lot of spoiled food disposed of, along with a freezer that we could never get the odor removed.
On our RV refer, when we are using it in sub-freezing weather, I always put a 40 watt bulb in the rear compartment, and partially block the air intake in order to insure that the refrigerant is circulated through the system.

Only One Old Fellow's Opinion


Bill
2002 Discovery 3126E CAT
2004 Saturn VUE
Mountain Master Tow Brake



Posted By: dougrainer on 12/13/07 05:10pm

Troubleshooter wrote:

While I won't try to go into the theory of why it happens, I personally know of a case where it has happened.
While moving from one abode to another, we put our freezer full of food in a unheated outside storage shed. Winter set in, and I didn't give it a second thought about the cold weather. About a week or so later the DW wanted me to get something out of the freezer, and when I opened it, you don't want to know what odors I was hit with. The temperature of the shed was about 10°F, whereas the internal temperature of the freezer was about 45°F.
Yes, it was plugged in, and there had been no power failure.
A lot of spoiled food disposed of, along with a freezer that we could never get the odor removed.
On our RV refer, when we are using it in sub-freezing weather, I always put a 40 watt bulb in the rear compartment, and partially block the air intake in order to insure that the refrigerant is circulated through the system.

Only One Old Fellow's Opinion


Was that freezer an RV absorbsion unit or a standard house freezer? Doug


Posted By: Troubleshooter on 12/13/07 05:42pm

Quote:


Was that freezer an RV absorbsion unit or a standard house freezer? Doug


Standard Freon/Compressor version.


Posted By: Good Samaritan on 12/13/07 08:36pm

Freshair, to answer your question...no your Norcold does not have any such feature. The reason it will not work in cold ambients is because it is a gas absorption refrigerator. Gas absorption refrigerators are different from your home refrigerator that utilizes a compressor. Gas absorption refrigerators require some type of heat input to the cooling unit (this is accomplished with either an AC tubular type heater, a flame via an LP burner or via a DC tubular heater)which in turn causes a chemical reaction in the cooling unit. The cooling of a gas absorption refer is based on Daltons Law. To keep things basic and in laymans terms, in order to make cold...you must add heat. The chemical reaction in the cooling unit is very sensitive to heat and COLD. If the cooling unit gets too hot...it won't cool hence the reason it is very important to ensure proper venting during the summer months. At the same time, the cooling unit is very sensitive to cold. If the cooling unit gets too cold it distrupts the chemicl reaction in the cooling unit and thus will not cool.Dometic, on some of their units have a LAC switch which simply powers the interior light on all the time. Although it is not entirely clear to me but I believe the reason they did this was that by adding a 10watt heat source (light bulb) in the freshfood compartment they effectively warm the thermistor which in turn keeps the heat source to the cooling unit on more often. Typically a gas absorption refrigerator will work in cold weather as long as you don't let the heat source to the cooling unit shut off. If the heat source is off and the cooling unit is allowed to get cold it is extremly hard to warm the cooling unit enough to get the chemical reaction in the cooling unit to "get going" again. Anyway, Norcold refrigerators do not employ such tactics and I think Dometic gave up on it as it didn't work very well?? If you disconnect the thermistor and set your temperature setting to 9 setting the Norcold refrigerator will run on a 100% duty cycle (what they refer to as a BOM ...Backup Operating Mode). Less chance for the cooling unit to get too cold. Just remember to plug it back in when winter is over. Good luck and Merry Christmas to all!


Posted By: dougrainer on 12/14/07 09:03am

1. Per Norcold--- Ambient below 20 to 25 degrees will see a big drop in absorbsion performance. Below real 0 degrees, you will see no performance. Norcold states also to NOT put any light or heat source in the back coil area (CYA for Norcold I believe).

2. Dometic states that to use the LAC below 32 degrees, but you will see a performance drop below 20 degrees even with the LAC on.

3. Both state to use LP gas as a fuel source below 32 degrees as the LP flame is more efficient in freezing temps. The LP flame will heat the back side area better than the insulated 110 elements.

4. Dometic states that they do recommend an additional 110 low watt lite source in the back area by the cooling coils.

5. Both state that the problem with absorbsion is sub freezing weather is the Ammonia mixture has some water and other chemicals that gel or crystallize in freezing temps.

6. In 30 years of RV service, I have never had this question come up.
You learn something new every day.


Posted By: dougrainer on 12/14/07 09:09am

"If you disconnect the thermistor and set your temperature setting to 9 setting the Norcold refrigerator will run on a 100% duty cycle (what they refer to as a BOM ...Backup Operating Mode"

In performance check outs per Norcold, they have stated they DO NOT want the refer in "BOM" for more than 24 hours. 24 hours is long enough to do a cooling unit performance check. Disconnecting the thermister puts the Norcold in BOM without even using the temp control. The temp control has no effect once the thermister is disconnected. In BOM, the refer will NEVER shut off, which is NOT a good thing in freezing or very cold temps. Doug


Posted By: Good Samaritan on 12/14/07 06:45pm

Doug,

When Norcold says not to operate any more than 24 hours in the BOM, they are refering to "suspect" cooling units. If you have a cooling unit that isn't cooling (possible blockage or what have you)you don't want to keep putting heat into it (these cooling units tend to run hotter than a "working" cooling unit and if you continue to apply heat to them you take a chance of rupturing them). The temperature selector determines the duty cycle of the BOM when the thermistor is unplugged. If the temperature setting is set to 9 with the thermistor unplugged the duty cycle will be 100%. If it is set to 5 then the duty cycle will be closer to 50% (in other words the heat source to the cooling unit will be ON for 30 minutes and then OFF for 30 minutes)All I was trying to point out is,as you said, there is water in the amonia solution and this water can and will freeze. This becomes possible when the heat source to the cooling unit is allowed to be powered off.Applying heat to the cooling unit 100% of the time in very cold temperatures will lesson the likelyhood of the amonia solution to freeze.Bottom line is gas absorption refrigerators don't like cold or hot ambients and these temperatures can and do have adverse effects on their ability to cool.Again, it is perfectly alright to run in the BOM for more than 24 hours providing you have a "working" cooling unit. In fact you could always run in the BOM if you wanted to and as I stated earlier, the BOM duty cycle is determined by the temperature setting selected.


Posted By: dougrainer on 12/17/07 07:52am

Good Samaritan wrote:

Doug,

When Norcold says not to operate any more than 24 hours in the BOM, they are refering to "suspect" cooling units. If you have a cooling unit that isn't cooling (possible blockage or what have you)you don't want to keep putting heat into it (these cooling units tend to run hotter than a "working" cooling unit and if you continue to apply heat to them you take a chance of rupturing them). The temperature selector determines the duty cycle of the BOM when the thermistor is unplugged. If the temperature setting is set to 9 with the thermistor unplugged the duty cycle will be 100%. If it is set to 5 then the duty cycle will be closer to 50% (in other words the heat source to the cooling unit will be ON for 30 minutes and then OFF for 30 minutes)All I was trying to point out is,as you said, there is water in the amonia solution and this water can and will freeze. This becomes possible when the heat source to the cooling unit is allowed to be powered off.Applying heat to the cooling unit 100% of the time in very cold temperatures will lesson the likelyhood of the amonia solution to freeze.Bottom line is gas absorption refrigerators don't like cold or hot ambients and these temperatures can and do have adverse effects on their ability to cool.Again, it is perfectly alright to run in the BOM for more than 24 hours providing you have a "working" cooling unit. In fact you could always run in the BOM if you wanted to and as I stated earlier, the BOM duty cycle is determined by the temperature setting selected.


I just talked to Norcold Tech Service to verify MY understanding of the Bypass (BOM) mode. Norcold stated that once the Thermister is disconnected, then NOTHING you do with the Temp set will keep it from going 100%. Once the Control board does NOT seem the Thermister Ohm readings, it goes to 100%. Can you tell us where you received your Info for your understanding of the BOM? Was it from Norcold? Doug


Posted By: Good Samaritan on 12/18/07 06:09pm

You may want to call that Norcold service technician back and point it out that the BOM is described in their service manual?! Look at either their of the service manuals for their current 12/8/6 models.


Posted By: John & Angela on 12/18/07 06:35pm

So here is a real world performance report on a 1200 series 12 cudic foot 4 door norcold on our 2003 Revolution that we have full timed in for four years.

We have been in sustained minus 25 celcius temps. During the day it would rise to minus 12 or so and at night as low as minus 25. Although it ran fine for the most part, at one point we got a "NOCO" fault. We reset it and it was fine for awhile. Then we got another (next night) and it needed to be reset by grounding certain test point to ground. Seems after a certain length of time that the thermostat doesn't call (in cold weather) the board will spit out a "NOCO" fault. An RV tech friend of ours took a look, blocked off two of the three air inlets at the back with tape and it ran fine for the rest of the cold snap. The ice maker valve never froze the whole time. ALthough we ran it on electric the whole time we have learned since then to run it on propane in this situation.

We have been lucky enough to relocate to warmer temps when the weather gets cold since that time.

* This post was edited 12/19/07 03:29pm by John & Angela *


2003 Revolution 40C Class A. 2002 Vanguard 22 foot Class C. Diesel smart car as a Toad on a smart car trailer or pulling a 2009 Timeout Tent Trailer.

Life is not measured by the number of breaths we take but rather by the moments that take our breath away.


Posted By: dougrainer on 12/19/07 07:49am

Good Samaritan wrote:

You may want to call that Norcold service technician back and point it out that the BOM is described in their service manual?! Look at either their of the service manuals for their current 12/8/6 models.


YOU are right and kind of wrong The service manual DOES state that when you go into BOM, it is a "Ajustable" cooling cycle. BUT, it does NOT explain what and how this is done. Norcold tech service explained that the adjustable is determined by the 1-9 temp setting like you described. According to Norcold, each number is the time it stays on. IE- set on 4, then it will run 40 minutes, set on 7 it will run 70 minutes and so on. I did not ask the shut off wait time before it comes back on. Do you know that time? But, do you think this will even work in temps below 20 degrees, since when the unit is NOT on, will the outside temp cause a problem with the coolant mixture? Doug


Posted By: Good Samaritan on 12/20/07 06:17pm

YOU are right and kind of wrong The service manual DOES state that when you go into BOM, it is a "Ajustable" cooling cycle. BUT, it does NOT explain what and how this is done. Norcold tech service explained that the adjustable is determined by the 1-9 temp setting like you described. According to Norcold, each number is the time it stays on. IE- set on 4, then it will run 40 minutes, set on 7 it will run 70 minutes and so on. I did not ask the shut off wait time before it comes back on. Do you know that time? But, do you think this will even work in temps below 20 degrees, since when the unit is NOT on, will the outside temp cause a problem with the coolant mixture? Doug

Doug,
The back up operating mode works like this:I have verified this operation on my Norcold refrigerator in my trailer.Ok, some days are more boring than others!

The BOM is activated anytime the refrigerator control senses the thermistor as electrically open or shorted. The BOM operation is dictated by the temperature setting. For the model refrigerator we are talking about,there are 9 temperature settings. Norcold set up the BOM on a 1 hour time period. So,doing the math one can calculate the duty cycle on and off times.

Temp.set on 9: 60*.10 60 = 100% (on all the time)
Temp.set on 8: 60*.9 54 = 90% (on 54min.off 6min.)
Temp.set on 7: 60*.8 48 = 80% (on 48min.off 12min.)
Temp.set on 6: 60*.7 42 = 70% (on 42min.off 18min.)
Temp.set on 5: 60*.6 36 = 60% (on 36min.off 24min.)
Temp.set on 4: 60*.5 30 = 50% (on 30min.off 30min.)
Temp.set on 3: 60*.4 24 = 40% (on 24min.off 36min.)
Temp.set on 2: 60*.3 18 = 30% (on 18min.off 42min.)
Temp.set on 1: 60*.2 12 = 20% (on 12min.off 48min.)
If you get bored, try this and you will see it is fairly accurate.

Now, the reason I suggested the thermistor be unplugged:

Going with the assumption the cooling unit is working ok to start with and then falls on its face as the temperatures drop lower and lower - my experience tells me that the off time (that is when the burner is off or the AC heater is off)is typically when the cooling units amonia solution can begin to freeze (water in the amonia solution freezes).

If the thermistor is unplugged, the heat output to the cooling unit will be on according to the duty cycle. With the temperature setting set to 9 the heat source will be on all the time. This heat source should retard the possiblity of the cooling unit to freeze.Notice I said retard not eliminate.All I am trying to say is by allowing heat to be present at the cooling unit 100% of the time the likelyhood of it freezing up would be lessoned as this is what I suspect has caused the refrigerator to quit cooling in the first place. Again, gas absorption refrigerators don't like heat and they don't like cold. If they get too hot they quit working. If they get too cold they quit working.


Posted By: pnichols on 12/28/07 01:39am

I just read this thread entirely because it gets into exactly what just happened to me in the last 24 hours with my rig sitting outside in the driveway!!

It's a 2 year old rig and the Norcold gas absorption refer normally works just fine. Over the holidays we were trying to use it's freezer compartment for extra capacity because of our entertaining, but with no one staying in the rig so we were keeping the interior just barely warmed with an electric heater on a very low setting, Outside temps were sitting in the 30-40 degree range.

I really think Chris Bryant nailed what is going on above ... " If it's very cold out, the lower portion of the refrigerator will maintain 35-40° without the cooling unit running, because on that model the only temperature sensing is in the fresh food compartment. Because the cooling unit isn't running, the freezer temperature will rise."

He describes EXACTLY our situation. My gut tells me it has less to do with what the outside temp may be and a way lot more to do with how warm it is inside your coach. That's why folks say they have no problem camping in the winter with low outside temps when using their gas absorption refers - their INSIDE temps most likely are not anywhere near as low as 35-40 degrees while they are living inside.

This morning I went out and the freezer and refrigurator are both sitting at around 38 degrees! Not good for the overflow stuff we had in the freezer. I turned it up to a higher cold setting to drive the freezer down below freezing but this then moved the refrigerator section below freezing too.

Neither the Winnebago or Norcold manuals said anything about this situation. It seems like they could at least clue you in about not operating the refrig while your rig is perhaps too cold inside during storage.


Phil, 2005 E450 Itasca 324V Spirit


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