Dometic & Norcold Agree


In this video Mark Nemeth, the technical advisor for the Escapees RV Club, explains how and why Dometic and Norcold refrigerators fail if they are not protected with the Fridge Defend by ARP.

We dedicate this page to the memory of our friend and mentor Roger Boisjoly, safety cannot be compromised.

Table of Contents

This page is divided up into video, links, further info on rust layer, and finally the timeline of patent events. Please view the subject matter on left and click link on right to go directly to the subject of interest.

Why Dometic & Norcold Fridge Fail Video

This video goes into the details of why cooling unit boiler overheating not only destroys Dometic and Norcld RV refrigerators, it also explains why the Fridge Defend improves reliability, efficiency, and safety.

Please click here for Mark Nemeth's RV Gadget Box article May 2014

Please click here for RV Gadget Box article May 2017

Further Videos and Proof as to Truth

Click here to see letter from Norcold to the NHTSA explaining the warp (thermal stress) of the boiler.
FYI: Norcold calls this event "low cyclic fatigue failure" in the boiler.

Click here to see video showing entire fluid flow within the Dometic or Norcold cooling unit.

Click this link to see boiler temperature and pressure test data video.

Click here to view video with Fridge Defend and a cooking pan, as long as there is fluid in the pan, it does not overheat.

Rust Prevention Layer

The following is a long history of recognition on behalf of the refrigeration manufactures that overheating the cooling unit boiler results in fridge destruction, the only defense is the Fridge Defend by ARP. Please note that Dometic was formed by Electrolux for the American market.

Passivation: "A thin film consisting of chrome and iron oxides (Cr2O3 and Fe2O4) is built up on the surface of the steel tubes and protects the apparatus from corrosion." The blue layer shown on the inside of the boiler tube in the video is technically a passivation layer. We name the layer a "rust prevention layer" as this is more of a layman's term.

Dometic & Norcold Patent Chronology - Fridge Defend is Necessity in their Words

For the following references, the brown italic font represents quotes from the references cited:

Click here to view a General Refrigeration History Timeline Starting in 1000 BC.

1930 Electroinz

US Pat. 1,960,040A

Title/Link: Corrosion preventing agent in the apparatus.

In this patent is it explained that "some of the corrosion preventing agents, upon decomposition, produce substances which themselves are corrosive". Therefore, when the boiler on your fridge overheats and the rust inhibitor is destroyed, the result is further destruction of the fridge.

Click here to see our c1937, 82 year old and counting, Servel referigerator.

1945 Electrolux/Dometic

US Pat. 2,580,983

Title/Link: Corrosion inhibitors in absorption refrigeration system.

This patent speaks for itself: "The main object of the invention is to increase the lifetime of the apparatus and to prolong the durability of the corrosion protection". Are we starting to form a pattern?

1965 Electrolux/Dometic

US Pat. 3,295,334

Title/Link: Heat operated refrigerator operable on gas or electricity and control mechanism.

This patent makes clear that "elevated temperatures which are within a safe operating range which does not impair the life of the refrigeration apparatus". We are starting to form a pattern! Click here for more on boiler temperatures and failure of fridge.

1971 Electrolux/Dometic

US Pat. 3,808,834

Title/Link: Boiler constructions for absorption refrigerating apparatus.

In this patent it is stated "the metal surface coming into contact with the working media in the boiler is increased and hence also the consumption of corrosion preventing agents in the solution which may lead to a shortened life of the refrigerating system". Thus it is well know that the life can be shortened for your fridge when the boiler overheats.

1976 Nicolas Eber

US Pat. 4,185,470

Title/Link: Object of the invention to limit corrosion.

We show this patent just to make the point that it is more than well known that corrosion is a confirmed issue based on "object of the invention to limit corrosion".

1980 Electrolux/Dometic

US Pat. 4,362,029A

Title/Link: Absorption refrigerator boiler construction.

It is very hard for the manufactures of RV refrigerators to state in their patent that the nature of the invention is to "prevent creation of undesirable excess temperature in the boiler" that "abnormally high boiler temperatures involve the risk that corrosion-protecting components, such as a type of chromates, added to the solution are consumed in a shorter period of time than what is considered to be normal." In addition, "influence on the cooling capacity of the refrigerating apparatus the above-mentioned disadvantages can negatively affect the life of the apparatus", where the apparatus is a Dometic or Norcold RV refrigerator. Then turn around and tell the public that the Fridge Defend by ARP is not necessary. Click here for more on boiler temperatures and failure of fridge.

1999 Dometic

US Pat. 6,282,918

Title/Link: Absorption refrigerating apparatus constituted to prevent corrosion inside it.

This patent is an attempt to change "the construction is such, that corrosion, and by that obstruction of the pump pipe is suppressed." which acknowledges that there is an ongoing issue with corrosion that is being attempted to solve. But so far only the Fridge Defend by ARP has solved this issue.

2002 Norcold

Letter from Norcold to NHTSA (National Highway Transportation Safety Administration)

Title/Link: We have determined that a defect relating to motor vehicle safety exists

Please note that this clearly demonstrates that overheating of the fridge boiler leads to " consequences of this fatigue failure can lead to the liquid solution slowly leaking from the sealed pressurized cooling unit through a small crack which could occur from the thermal expansion created " leading to a fire " ignited by the high temperatures " of the boiler assembly, or restated: " thereby possibly causing a fire ".


US Pat. 8,056,360

Title/Link: Absorption Refrigeration Protective Controller (ARP Control).

Please note that the manufactures of the refrigerators filed all of their patents that related to boiler overheating and subsequent hazard after our patent was published.
Fridge Defend by ARP Fridge Defend protects Dometic & Norcold

2007 Dometic

US Pat. 8,874,178

Title/Link: Absorption refrigerator flame arrestor system and thermodisc, thermofuse, or thermal fuse.

If there is "an abnormal rise in temperature near the boiler" requires a "containment system", would it not be better to just keep the boiler from getting too hot like the Fridge Defend already does?

Click here for more on Dometic "Thermofuse", "Thermal Fuse", or Thermal Switch" recall.

2010 Norcold Application


Title/Link: Absorption refrigerator unit with temperature and level monitoring.

As soon as we are granted a patent for the Fridge Defend by ARP, Norcold applies for "preventing the boiler from operating at high temperatures can avoid consumption of sodium chromate, which can be used in the coolant mixture to neutralize any corrosive effects of the ammonia solution " patent. But, one cannot re-patent the same invention so the application was denied.. Click here for more on Norcold attempt to make the Fridge Defend for themself.

2011 Dometic

US Pat. 9,228,773

Title/Link: Tilt monitor and stress controller for absorption type refrigerator.

It is clear that Dometic RV fridge "boiler can reach abnormally high temperatures" so they deal with it by "limiting the time of operation of the refrigerator", would it not be better to just keep the boiler from getting too hot so you do not have to buy a new refrigerator or suffer a failure that may be dangerous? Click here for more on Dometic patent which does not protect the fridge nor the owner.

2012 Norcold Letter to ARP Control (Fridge Defend)

Recall Kit 634737

RE: Why Recall Cannot Protect Boiler

Title/Link: Click here for more on Norcold comments to us and the NHTSA.

Norcold informs us that "heat input to the cooling unit is not adjusted until a sensed temperature of over 800°F. Such temperatures are only experienced at the location of the Norcold sensor if the cooling system experiences a leak ", and a leak is the most common source of a fridge fire.

2012 Fire in Montana -- Almost Kills Owner

See: 2007 Dometic US Pat. 8,874,178 (above)

RE: This Recall is Installed

RV Fridge Fire Dometic 2012

The fire above occurred shortly after a full inspection of the RV, the refrigerator was inspected. The owner is an experienced RV'er. This fire occurred in the early morning hours, the owner stated that he came close to being killed by the incident. The fire chief reported that the recall must not have been installed, but the red circle shows Dometic's "Containment System Thermal Switch 230, click this link to read about recall and Thermal Switch 230. Thus the recall was installed and a fire occurred regardless.

2014 Dometic GmbH

Dometic Public Application - European Union

Title/Link: Protect the cooling unit from corrosion is reduced at high temperatures (Less than 180°C).

Marked up Version of Above Document: Download marked up document, page 67: " If a cooling unit is tilted more than a few degrees the pumping will cease. This will cause a higher boiler temperature that will increase the corrosion rate. "

"The whole unit operates by the heat applied to the boiler system and, for a good operation, it is of paramount importance that this heat is kept within the necessary limits and is properly applied ", therefore the Fridge Defend is required by this statement. Just as the title states, the Fridge Defend by ARP limits the boiler temperature by "protect the cooling unit from corrosion is reduced at high temperatures (< 180°C)" when the system pressure is set properly.

2018 Thanksgiving Day Fridge Fire

Title/Link: Click here for more on the story "I believe in the science regarding how the Norcold 1200 absorption works, or doesn't work. I trust opinions which are based on science. My original 1200 worked GREAT for 7-1/2 years. I suspect it would've gone longer if the Fridge Defend by ARP safety device had been installed" RV Fridge Fire Thanksgiving 2018

03-18-2019 Fire Last Night at Riverside RV Park in Laughlin NV - Norcold Frige

Title/Link: Click here for more on the story.

"So sad! I just don't understand why folks won't make the small investment in the ARP protection device to know that they are safe."

RV Fridge Fire 03-18-2019

03-24-2019 Norcold Refrigerator Fire - Lost Everything

Title/Link: Click here for more on the story.

"We just experienced a horrific fire caused by our Norcold refrigerator and we have suffered a million dollar loss and lost everything."

RV Fridge Fire 03-24-2019

05-03-2019 Norcold Refrigerator Fire - Colorado

Again, the fire inspector was reported to ask if the recall was installed? See red circle in photo, Norcold recall was installed, click this link for more on Norcold recall.

RV Fridge Fire 05-03-2019

* The animations on this page are not to scale, they are amplified for visual effect so as to better clarify the events that occur. The events depicted in these videos are not sequenced as they actually occur, rather they are presented in steps so the viewer can better understand the science behind the method of failure. Most of the events in this video occur simultaneous, this is why the Fridge Defend has a 2 second reaction time to thermal events and approximately +/-2ºC accuracy at typical boiler temperatures.