Norcold “Cooling Unit Failed” – what does that mean?

[RustyTools]

Norcold “Cooling Unit Failed” – what does that mean?


Let me preface by saying I’m NOT bashing Norcold, Dometic, or anyone else – I just want to understand what's going on.

My 3-year old Norcold 1210LRIM went out recently. Freezer sections get down to maybe 12F but the frig part barely goes below inside ambient (68-70F), with 85F outside. On the backside, the vertical burner tube gets very-very hot, while the outside fins at the top are barely warm to the touch – except for the first tube which does get hot. The bigger coils at the bottom are hot down low but progressively cooler as they go up. Pretty-much ambient temperature where the tube sections meet about ½ up the box. But I seem to remember it all of the tubes getting hot on the outside before.

From everything I’ve read, and taking it to 2 different repair locations, points to the same diagnosis each time: the ‘cooling unit went out’. No ammonia leaks or other damage, checked the thermistor (it’s working), the AC heaters (they’re working), the LP burner assembly (it’s all working)… and so on.

I saw several suggestions about ‘burping’ the unit, which involves taking it out of the wall and rotating it each of its sides for 15-30 minutes with the idea in mind that it releases a vapor-lock condition, but there seemed to be a caveat that newer units wouldn’t benefit from it. I tried it anyways, no luck.

Based on everything I can get my hands on about these units, some failures are obvious… Things like ammonia leaks, failed heaters, bad circuit boards, I definitely understand. But what does it really mean when they say the cooling unit is bad? Does it mean that there’s an obstruction in a line somewhere? The ammonia has separated internally? Hydrogen leaked out? What actually went wrong, and is there a way to overcome it? Why does the unit get hot in some places and not others?

And what is a reasonable temperature differential, like between freezer & frig box (I’ve heard 30F, but is that valid), or between outside & frig box, etc?

In other words, what exactly failed… and why?


Thanks in advance!

[Jack R]

Rustytools

There have two recalls on the Norcold I know of. Have you had these completed.

Alot of folks appear to be replacing the Norcold cooling unit with a Amish cooling unit and are happy doing so.

Search Amish cooling and you should find more information on this.

jack

[tennessean]

Rusty Tools

My 2011 winnebago journey's Norcold is at the repair shop now for the the very same thing you describe-freezer is cold; refrig is 60+. I also went through all the testings. The dealer has ordered a new unit. At least mine is under warranty.

Tennessean

[SUMDALUS]

RustyTools,

RV refrigerators are basically designed to maintain the following cold temperatures:

Freezer: 0 to 10 degrees F
Chill Box: 38 to 40 degrees F

These temperatures are considered to be in the ‘safe’ ranges for proper food storage and are considered ‘normal’ for an Absorption refrigerator.

For more information concerning the RV Refrigerator, you may want to check out my series of blog postings about "Understanding the RV Refrigerator". The latest posting is HERE. It specifically has to do with Cooling Unit Failures.

Hope this helps.

[Sammie]

Quote:

Originally Posted by RustyTools Norcold “Cooling Unit Failed” – what does that mean? Let me preface by saying I’m NOT bashing Norcold, Dometic, or anyone else – I just want to understand what's going on. My 3-year old Norcold 1210LRIM went out recently. Freezer sections get down to maybe 12F but the frig part barely goes below inside ambient (68-70F), with 85F outside. On the backside, the vertical burner tube gets very-very hot, while the outside fins at the top are barely warm to the touch – except for the first tube which does get hot. The bigger coils at the bottom are hot down low but progressively cooler as they go up. Pretty-much ambient temperature where the tube sections meet about ½ up the box. But I seem to remember it all of the tubes getting hot on the outside before. From everything I’ve read, and taking it to 2 different repair locations, points to the same diagnosis each time: the ‘cooling unit went out’. No ammonia leaks or other damage, checked the thermistor (it’s working), the AC heaters (they’re working), the LP burner assembly (it’s all working)… and so on. I saw several suggestions about ‘burping’ the unit, which involves taking it out of the wall and rotating it each of its sides for 15-30 minutes with the idea in mind that it releases a vapor-lock condition, but there seemed to be a caveat that newer units wouldn’t benefit from it. I tried it anyways, no luck. Based on everything I can get my hands on about these units, some failures are obvious… Things like ammonia leaks, failed heaters, bad circuit boards, I definitely understand. But what does it really mean when they say the cooling unit is bad? Does it mean that there’s an obstruction in a line somewhere? The ammonia has separated internally? Hydrogen leaked out? What actually went wrong, and is there a way to overcome it? Why does the unit get hot in some places and not others? And what is a reasonable temperature differential, like between freezer & frig box (I’ve heard 30F, but is that valid), or between outside & frig box, etc? In other words, what exactly failed… and why? Thanks in advance!

Rusty, In my limited experience, a bad cooling unit can be either a leak where the ammonia has escaped. You may not have noticied it if you had the rig in storage when it happened. Or a blockage somewhere it the system tubing. In either case you may have to replace the cooling unit. If you go the replacement route, the Amish Built Cooling Units are an excellent way to go. If you are mechanically inclined you can do it yourself and save $$$$.

Here is a slideshow video of my personal experience in the replacement of my Norcold 1200 cooling unit.

‪Norcold 1200 to Amish Cooling Unit Conversion.mpg‬‏ - YouTube

If you have any questions, please ask.
Sammie

[GPW]

Seems any other product with this history would be long out of business ... Hope their toilets work better than their reefers...

[Dr4Film]

Quote:

Originally Posted by GPW Seems any other product with this history would be long out of business ... Hope their toilets work better than their reefers...

Their toilets are glorified Boat Anchors. Finally got rid of my Thetford Aria II POS. I sold it for $300, one of the best deals I have ever done, well for me that is.

I replaced it with the Dometic Sealand Magnum Opus. Now that's a REAL toilet. All china, big elliptical seat, huge bowl so the water doesn't splash out, variable water levels to choose from, etc.

No more Norcold cooling units, no more Thetford toilets for me. They need to go back to the drawing board and come out with something that really works.

Dr4Film ----- Richard.

[RustyTools]

Thanks to all, especially Sumdalus, for the very informative answers. Sammie's video is useful too on replacing the cooling unit.

Oh, by the way... I do not have the recalls done - I understand they are for overheating issues (somewhat ironically) which isn't my problem here, and I was waiting for a 'real' solution to a design issue and not a band-aid patch. And the unit was in a coach with a roof-vent.

Still can't quite get thru my head what failed (in the frig, not my head!). Best lead so far sounds like a piece of something (rust suggested?) got dislodged somewhere inside and caused the frig to basically 'stroke out'. That I do understand.

I've seen comments about the back insulation coming loose and letting air in/out or maybe the door seal not sealing, but those I'm not convinced are on the right track. If so, why would either of those happen essentially overnight then? And why is the inside freezer plate frosted-up yet the inside refrigerator coils barely cool to the touch after 24 hours?

I have the entire unit out of the cabinet (I tried to scare it by reminding it that this was the first step to the city dump!) and noticed that the entire exterior backside, and especially the fins at the very top, are only a few degrees above ambient - and nowhere near hot enough to cause the thermistor/fans to click on. In other words not enough heat, or maybe not in the right places.

Which brings up another question... faced with my dilemma, would you just buy a replacement cooling unit (probably the new Amish one) or swap it all out for a residential unit (knowing there will be a good amount of extra work to get it to fit - not to mention $$$) instead? And why?

Please pardon my rambling musings here, but I am casting about for any enlightenment as to why this thing is doing what it is. And if there is any salvation before plunking down several big-large. Seems like there's enough similar threads on here that this is a quite popular discussion.


Again, thanks.

[two gone rvn]

Amish unit all the way. Did mine last year and I would recommend them a 1000 times. Not only do they work better than the factory unit, but they are made better and in the USA. Give them a call, you'll be glad you did.

[RustyTools]

Sounds like an excellent recommendation to me, George, appreciate it.

Thanks all, for putting up with my saga here. I have another new installment to add to the tale ...

We spent the day looking at different frigs all over town. Got home and the frig fins are at 31*F and the freezers are 1.2*F and 9.3*F. Not bad numbers anytime, at least from my experience, and this is with the refrigerator side of the coach in the sun all day.

Ok, so how is it that it seems to be healing itself?? (only thing I can think of is that I defrosted the freezers a couple weeks ago, and maybe some water leaked down behind the freezer-box and created an insulation barrier to the plate when it started refreezing and is now slowly evaporating?)

[wa8yxm]

A better question is: How does the Fridge's computer detect the cooling unit has failed?

I can think of only one way to do it, By measureing the temp inside and outside when the unit is operating over a period of time.

If the unit does not cool fast enough.. Must be a failed cooling unit.

And....Under some conditions... I can see it not cooling fast enough, The very conditions we have been having lately.. My "personal" cooling unit (My body's cooling system) failed me today,, Heat Exhaustion it's called. Thankfully I know how to treat that so I seem to have recovered.

[SUMDALUS]

Actually, wa8yxm, the refrigerator control board is incapable of detecting a failed cooling unit.

What the board looks for is an indication of an "active" heat source (AC or LP) within a specific time period. If the board does not find what it is looking for, it signals either a "n" or "no co" (no cooling) error code. All based on the lack of generated heat to make the system work.

The first time a "n" or "no co" code shows up on the control panel, the owner can clear it by turning the refrigerator OFF, then back ON.

If a "n" or "no co" code shows up again, the board locks out all heat sources. Now the board must be reset by an authorized service center after troubleshooting and testing the cooling system operation.

It takes human observation and testing to detect a failed cooling unit.

And, according to Norcold, poor cooling unit performance may be due to:
..Loose insulation interfering with the ventilation process.
..Construction material or debris left in the "chimney" enclosure.
..Customer installed Insect Screen covering vents.
..Plastic sheeting covering vents.
..Items stored in the "chimney" enclosure.
..Modifications to vents or enclosure.
..Blocked or no roof or sidewall exhause vent opening.

You'd be surprised what we find on the backside of the refrigerator!

Hope you have fully recovered from your personal "overheating" problem. Heat exhaustion is serious stuff.

[Gary RVRoamer]

The latest Norcold recall fix attempts to determine if the cooling unit has failed by installing a thermistor (temp sensor) on in the boiler. Looks for excessive temperature there and shuts down if found.