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Old 07-02-2016, 06:42 AM   #1
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Refrigeration Problem

Hi,

We have a Nova Kool front load refrig/freezer. We were last on the boat 3 weeks ago and it worked fine. Shut it off while we were away and left the doors propped open.

Returned to the boat yesterday and now the freezer section is working great but the refrigerator is not cooling after 14 hours of operation. There is only one thermostat for the unit. There is not much info in the operators manual but there only appears to be one compressor.

Any ideas on what the problem might be? Hate to live out of the cooler all weekend. Section of the control module bad? Is there a solenoid valve that regulates refrigerant flow to the refrig that could have failed or be stuck.

All ideas welcome.

Gene
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Old 07-02-2016, 06:49 AM   #2
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Hi,

We have a Nova Kool front load refrig/freezer. We were last on the boat 3 weeks ago and it worked fine. Shut it off while we were away and left the doors propped open.

Returned to the boat yesterday and now the freezer section is working great but the refrigerator is not cooling after 14 hours of operation. There is only one thermostat for the unit. There is not much info in the operators manual but there only appears to be one compressor.

Any ideas on what the problem might be? Hate to live out of the cooler all weekend. Section of the control module bad? Is there a solenoid valve that regulates refrigerant flow to the refrig that could have failed or be stuck.

All ideas welcome.

Gene
Usually these type fridges only have one set of cooling plates. They freeze and the cold air cools the fridge. Some have a fan to assist. At least on the top freezer models.

The bottom line is they are very marginal at getting cold...they do better once cold.

I think the owners manuals even say cool the food and fridge first before cooling. I know ridiculous, but the price we pay for low power, efficient fridges. At least in this configuration...yes, yes, better but won't fit or please many boats.

Maybe this was your problem?

If you have the manual it may help or find it on the web. If not post the model and someone may have one or know of possible issues with that model.
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Old 07-02-2016, 07:01 AM   #3
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It is a model RFU9000, fridge on top, freezer bottom and it has two cold plates, one in each compartment.

Normally the fridge is <40 F in about 4 hours but after 14+ it has not cooled at all but the freezer section has everything frozen solid.

I have the IOM and also went on line to Nova Kool and downloaded the latest version. Nothing in the trouble shooting section specifically addresses this problem.

Something, probably a valve, has to send refrigerant to each of the cold plates. So I am thinking that it is either that device, the thermocouple on the fridge cold plate is bad or perhaps something in the control module that cycles the refrigerant flow.

Just wondering if anyone has seen this specific problem before.

Thanks,

Gene
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Old 07-02-2016, 07:20 AM   #4
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Sorry, guessed wrong....

Belay my last....

Good luck....
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Old 07-02-2016, 08:35 AM   #5
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Might have to much stuff packed in the freezer not allowing the cool air to drop to the fridge. To answer your question though, no.
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Old 07-02-2016, 08:44 AM   #6
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I just have a cheezy 28yr old Norcold, and had the same experience when I fired it up after sitting for 6 months. Took DAYS to get the Fridge section down to 40 degrees.

As psneeld said:

"they are very marginal at getting cold...they do better once cold."
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Old 07-02-2016, 09:23 AM   #7
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Thanks to everyone for the replies. Several clarifications -

freezer section is on bottom so not an issue with cold air dropping, each section has it's own cold plate so the freezer is not sending cold air to the fridge.

Just pulled the ECM per the owner's manual and checked resistance between the compressor plugs. The manual is vague - just says resistance should be approximately equal. I have ~47% difference so it may be the module.

Easily replaced - just not on July 4th weekend. Also noticed that the cooling fan is not running so that may be related issue since it is fed from the same ECM.

Plenty of free ice at our marina so in problem keeping the beverages cold!

Everyone be safe,

Gene
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Old 07-02-2016, 09:51 AM   #8
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have you checked the refer compartment control?
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Old 07-02-2016, 10:33 AM   #9
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There is only one control and it is located in the fridge compartment. I think, but am not sure, that the freezer goes to max regardless of what the setting is on that control.

That is a good suggestion but I am not sure how to trouble shoot it. Looks like it can be removed and replaced.

Gene
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Old 07-02-2016, 10:42 AM   #10
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since there are two cold plates there must be a wire for each. Can you test the voltage at each. If you can get to the control see if it has relays. If so a sharp rap on the relay may free a stuck one or force a better connection if the contacts are dirty.
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Old 07-03-2016, 06:11 AM   #11
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IF the freon path is shown in a diagram , the question becomes does the gas expand in the freezer and then passed on to the fridge plate?

Or are there two gas lines , one to each plate?

If its the latter the fridge plate probably has an ice chip in the pin hole, defrost the box and try again.

If its simply being passed on from freezer to fridge perhaps the freezer plate is not yet frozen so there is little energy left for the fridge.

I would get a chunk of foam and cover (insulate) the freezer plate from the freezer section, and see if it doesn't cool the fridge better.

Maybe you are just low on refrigerant?

2 individual plates is a challenge as to freeze well the temp has to go about 5-8deg below the plates melting temp, and stay there for a long time. Ice ( frozen eutetic solution) in the plate is an insulator.
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Old 07-03-2016, 09:51 AM   #12
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Hell FF,

There is only one discharge line from the compressor and of course no diagram for the coolant path in the IOM.

Based on what I can see of the tubing that feeds the cold plates it appears that from the condensor it feeds the plate in the freezer and from there to the plate on the fridge. I am basing that on what I read in Calder on refrigerant systems and that the smallest diameter tubing (capillary sized) is connected to the freezer plate and the largest diameter tubing is on the plate in the fridge. Makes sense based on p/v relationship for the refrigerant.

Not sure I am following the suggestion on isolating the freezer cold plate, could you explain the thought behind that a little more please?

Your comment about ice chip is intriguing - I noticed yesterday that the refrig tubing feeding the cold plate in the fridge were cool and sweating. Although I said the fridge section is not cooling it is in fact cooler than the boat. Right now I am defrosting the freezer (I checked it and it was at 0 F still) and in a bit will start over.

Refrigerant could be low but there does not appear to be a sight glass anywhere to verify that. We are not leaving the boat until Tuesday so that morning I will be on the phone with NovaKool to see what they suggest.

Thanks for your suggestions,

Gene
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Old 07-03-2016, 11:14 AM   #13
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FF - forgive my typo!

Should have been Hello! Must have been what I was thinking about the refrigerator.

Gene
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Old 07-03-2016, 01:42 PM   #14
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I have a Norcold fridge and on the advice of a appliance repairman I leave it on 24/7 year round. The freezer will freeze meat rock hard, it's less work keeping the compartment cold than making it cold when you decide to put it back into service.
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Old 07-04-2016, 07:13 AM   #15
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"Not sure I am following the suggestion on isolating the freezer cold plate,"

The refrigerant must retain enough liquid to evaporate in the fridge section to lower the temperature to below the eutetic fluid freezing point.

I suggest covering the freezer plate to assure its freezing solid and having liquid to pass on the the 2nd plate.

IF the freezer box absorbs too much of the coolant energy , the freezer plate wont get to a low enough temp to finally freezing the eutetic fluid , and have cooling to pass on.

The outlet for the fridge plate should be frosting if the system is running cold enough.

Fridges seldom have sight glasses or easily replaceable dryers.

IN FL the fridge folks ask the snowbirds to just leave fridges on all summer , while absent.

But that's hard to do in a boat/RV setup.
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Old 07-08-2016, 09:32 AM   #16
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Also noticed that the cooling fan is not running so that may be related issue since it is fed from the same ECM.

Gene
Gene, is this a 12 or 120 volt unit? try spinning the fan to get it moving again, before you pull things apart. Little fan motors tend to have sticky bearings that loosen when warm.
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Old 07-08-2016, 02:43 PM   #17
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What brand of compressor is this? If Danfoss, they have an easy to use troubleshooting guide.


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Old 07-08-2016, 07:54 PM   #18
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If refrigerant gas is low, doesn`t that mean it has gone somewhere (contributing to the now resolving ozone layer hole)? Meaning there is a leak?
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Old 07-08-2016, 08:51 PM   #19
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Whoa! Unless the fridge is really old it's probably charged with 134a and likely under 5oz. If already found the fan not running, soooo, let's wait n see if he updates us
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Old 07-11-2016, 06:58 AM   #20
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Time for an update.

Fan - the fan is okay, the negative lead for the fan went from the ECM to a thermal switch. I jumped those leads and the fan worked fine. When I talked too NovaKool they said to eliminate the switch as they no longer use one. Installed a butt splice, and that problem is solved.

The issue was low refrigerant level. It was topped up on Wednesday of last week and as of Saturday was still holding but I suspect that there has to be a small leak somewhere. We left the refrig on for this week and plan on returning to the boat Thursday night. Hopefully the temp in the fridge will be the same as when we left, if not then the hunt for the leak begins.

Thanks for all of the suggestions.

Gene
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