Another cooling unit - long story

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Ned

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As some of you may recall, our original Dometic cooling unit failed in the fall of 2013 and we replaced it with an Amish cooling unit.  We also installed the ARP control at that time.  The motorhome has been parked all winter with the refrigerator running, until last week.  Lorna went out to start getting the motorhome ready for our departure on May 9 and noticed the ARP was displaying OFF and the refrigerator was off.  I reset everything and the refrigerator started up, and shortly it was again shut off by the ARP.  Since I have the ARP monitor with the data output, I hooked up my netbook and collected some test data while the refrigerator was running.  It showed the boiler temperature rising steadily to about 190?C at which point the ARP shut it off.  Normal boiler temperature for my unit is about 160?C.  After some email exchanges with Paul Unmack, the ARP inventor, I put the ARP into recording mode where it doesn't shut off the refrigerator, but just records the boiler temperature.  This time the temperature rose to 206?C and stayed there.  I repeated this with similar results.  Paul diagnosed this as a loss of the ammonia in the cooling unit.

Today we had a mobile RV tech over for some other work and he looked at the cooling unit.  When we opened the outside compartment, we both got a strong smell of ammonia, confirming Paul's diagnosis.  The cooling unit comes with a 3 year replacement warranty so I called the original seller, RV Cooling Unit Warehouse, and he requested an email with the details.  I sent that and received an almost immediate reply from JC Refrigeration, the manufacturer, along with a warranty form.  He requested a photo of the leak, but since that's not possible until the unit is removed, I sent some photos of the outside compartment that shows some yellow residue, also from the leak.  Upon emailing the warranty form and the photos, I received another prompt reply telling me that the replacement cooling unit will ship tomorrow.  I couldn't ask for better service than this.

I believe that the ARP control probably saved us from more serious problems, like a cooling unit fire, by shutting the refrigerator off before the temperature could get, and stay, too high.  This is the second time the ARP has prevented a serious problem, I am sure.  The previous was when we were towed last spring and we didn't turn the refrigerator off before the tow truck hooked up.

With luck, the cooling unit will get here early next week and we can get it installed before the weekend.  If it's delayed, we'll have to delay our departure and may miss some of the Palo Duro Canyon rally, but we're still thinking positive :)
 

Kevin Means

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Ned said:
I believe that the ARP control probably saved us from more serious problems, like a cooling unit fire, by shutting the refrigerator off before the temperature could get, and stay, too high.  This is the second time the ARP has prevented a serious problem, I am sure.  The previous was when we were towed last spring and we didn't turn the refrigerator off before the tow truck hooked up.

No kidding! I've heard nothing but praise for those ARP units.

Kev
 

Tinmania

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You would think with the cost of RV absorption refrigerators that the manufacturers could put a simple high-temp cutoff device on them of some sort. (Do any?)

Regardless, I have the ARP site bookmarked. Getting a little hot around here but maybe come fall....




Mike
 

Ned

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Both Dometic and Norcold had recalls where they install a catastrophic cutoff device, but that only activates when the temperature is so high, the unit is probably already on fire.  The ARP control is what should be designed into every RV absorption refrigerator.
 

Gary RV_Wizard

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Disappointing that a new cooling unit failed so quickly, though. I've seen a few other reports of early failures too. Some may have been poor installations, but since Paul Unmack personally installed yours, I'm confident that it was done right. He is a professional mechanical engineer and really meticulous about his work!
 

Rene T

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Gary RV Roamer said:
Disappointing that a new cooling unit failed so quickly, though. I've seen a few other reports of early failures too. Some may have been poor installations, but since Paul Unmack personally installed yours, I'm confident that it was done right. He is a professional mechanical engineer and really meticulous about his work!

The way I read the post, I don't think Paul personally installed it.  He merely was contacted to get his opinion. I think. :eek: ::)
 

zmotorsports

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Hope it shows up and you are able to get it swapped out before PDC rally Ned.

Mike.
 

Ned

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Paul did the install. I documented it here.
 

Betty Brewer

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Ned, your issue sort of makes my bathroom vanity light failure look whimpy.  Good luck with the fix and hurry to meet us.  We are on our way!
 

Ned

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Betty, we've pushed our departure back to Monday, so should arrive at PDC on Tuesday.  Assuming all goes as planned next week.  The new cooling unit is on the way via UPS and scheduled for arrival here on Wednesday.  I've got the local RV techs scheduled for all day Thursday.
 

Ned

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The cooling unit arrived a day early, on Tuesday, (thanks Mr. Brown :) ) and our mobile tech came on Thursday and installed it.  The installation cost almost as much as a new refrigerator, but Paul wasn't around this time :(  Unfortunately, during the installation, somehow the RTD (temperature sensor) for the ARP control got shorted to ground and it's too far up the boiler tube to reach from outside.  We were not going to pull the refrigerator out again to check the wiring, so we're temporarily without the ARP control safety.  Paul will send a new RTD when we get to Milwaukee and it will be installed from outside, lower on the boiler tube.  The new cooling unit is working as expected.  After I sent some photos of the leakage, the manufacturer didn't want the old unit back.  See below for what a failed boiler looks like.  The yellow is the sodium chromate, and we could still smell the ammonia on Thursday.

We're now on our way and will be at Palo Duro Canyon tomorrow afternoon, barring some other catastrophic failure :)
 

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Gary RV_Wizard

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Obviously the failure must have been "operator error", since it is well-known [on the internet, anyway] that an Amish Cooling Unit is the nearest thing to perfection this side of Heaven. Viewing its many praises, one wonders if it even needs to be powered up to keep the food cold!  So fess up, Ned. What did you do to ruin it?  ;)
 

Ned

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Don't blame me, Lorna was the one who said it stopped working.  It was fine every time I checked it. :)
 

Ned

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Not unless this cooling unit dies too.  Being a double door Dometic, there are very few, if any, drop in residential models.  I would probably look at a marine compressor model instead.
 

Daleg1970

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Interesting story

I just installed the amish cooling unit about two weeks ago, and this next week will install the ARP controls.
Your info tells me I am glad I got the ARP controls.

As alluded to, the amish units will have a failure rate like any mechanical object.  I just hope that it is not very high as no one yet probably has ten years of usage.

thx Dale
 
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