How to Find Information on This Site Video (CLICK HERE) .

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Want to Solve your Dometic & Norcold Cooling and Safety Issues?

The Fridge Defend® solves the root-cause resulting in the failure of these otherwise great refrigerators.

The Fridge Defend® is the most effective solution for Dometic and Norcold refrigerators, it solves cooling issues while helping to save lives and property due to RV fridge fires.

NFPA statistics ( National Fire Protection Association ) show that 57 million dollars per year of damage is incurred by RV owners and insurance companies.

Immeasurable Expense is what is felt by the victim of an RV fire after loosing a loved one or a lifetime of memories.

See Fridge Defend necessary for Dometic and Norcld video to see what happens to your fridge climbing Mountain Springs Grade I-8, CA.

Worn down by issues with recalls such as 'no co' or fridge shut downs for no apparent reason? The Fridge Defend is the best solution for keeping your fridge cool in hot weather while avoiding these recall problems. When the Fridge Defend is on duty, it not only saves lives and property, it can be the difference between a fun outing, and a disastrous and troubled vacation.

Please see next video and click to contribute to a victim of refrigerator fire

Dometic and Norcold absorption refrigerators are driven by a fired boiler. It is considered good engineering practice to monitor fired boilers for thermal run away conditions with a safety controller. The patented v5.x Fridge Defend is an accessory IEC type safety controller that uses standards, including applicable ( and practical ) IEC 60730 automatic electrical control checks, combined with functional self-tests to provide an economical, yet functional safety control.

Get the Fridge Defend - be COOL be SAFE!

LET US KNOW HOW WE CAN HELP?: ARP wants to help with all your needs for Dometic and Norcold refrigerators. If you cannot find what you are looking for please use the Contact Us form.

Paul and Mao Unmack, Fridge Defend

Who are We?
Why our Product is Praiseworthy

Paul and Mao Unmack are practitioners of engineering science that have committed themselves to RV safety. We are not sales people, we do not push product you do not need. We at Fridge Defend hold paramount the safety, health, and welfare of the public. This website is presented only in an objective and truthful manner and is based on sharing our extensive RV experience.

Read on to be motivated by the praise from both Dometic and Norcold, top RV advisors, all combined with customer testimonials, the foundation of any praiseworthy product that provides value.


As is apparent by the proofs below, Dometic & Norcold studied the failure mode of their RV refrigerators. Start by reading how important controlling boiler temperature is, then go down in this page and view the Dometic & Norcold root cause analysis 'Fishbone' diagram.   


Dometic Engineering Document (Page 16 & 55)

"The whole unit [refrigerator] 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."

Click here for entire Dometic Engineering Document

Norcold Patent Application 13/279,361 (Par. ¶ 0036)

"Preventing the boiler from operating at high temperatures can avoid consumption of sodium chromate ... the cooling arrangement temperature sensor can be positioned on the boiler tube."

Click Norcold's failed attempt to re-patent Fridge Defend

Norcold (Par. ¶ 0025) Backs Up Dometic (Page 57) & Fridge Defend Documentation

"It is desirable to operate the [boiler] heat sources of the cooling arrangement within an optimum temperature range ... boiler temperature is believed to be the single most important factor for corrosion."

Click here to read more from Norcold

Dometic (Page 25 & 67) Backs Up Norcold & Fridge Defend Documentation

"This is also a matter of product safety ... [refrigerator] life length is in other words critical both for customer satisfaction and product safety". "The corrosion rate is increased when the boiler temperature is increased."

Click here for entire Dometic Engineering Document


Dometic and Norcold Facts

The Fridge Defend monitors "the corrosion reaction rate [which] depends on temperature and flow conditions.", where flow conditions determine the production of refrigerant by the boiler of Dometic and Norcold RV refrigerators. Thus, it is confirmed, the root cause of failure is solved, which is also confirmed by the science of temperature dependence of reaction rates, and years 1930 through 1999 Dometic/Electrolux document chronology.
What more proof is needed?

The Fridge Defend not only saves you money and valuable vacation time, while giving you added life and property protection, it protects the "environment"! Best of all, the Fridge Defend re-starts the fridge after a protection cool down period, so that your food doesn't spoil. All without any effort by you!
Dometic Engineering Document (Page 17 & 20)

Click here to see video that shows the facts from Dometic & Norcold statements .

Being a retired fire chief, I know the value of fire prevention and also know firsthand the destruction, loss of life, pain, and agony that can go along with accidental and unwanted fire. So I strongly endorse the Fridge Defend by ARP for anyone who has an absorption RV refrigerator.
Mike Burger, Kochville Fire Chief (Ret.)
I am very happy with the Fridge defend and the support Paul & Mao provide.
The ARP improves safety and reliability, and that’s a great gadget!
Mark Nemeth, Escapees RV Club Technical Advisor
Last summer we had a series of flat tires on our 5th wheel. We never worried about our fridge when the trailer was not level on the side of the road. The Fridge Defend protected the fridge from overheating damage, which shortens the life of the fridge. Bob Livingston RV/MH Hall of Fame & Editor Trailor Life Magazine
To me the ARP Controller is a requirement.
I would not operate a Dometic or Norcold RV fridge without the protection the Fridge Defend offers. Brett Wolfe
FMCA Technical Advisory Committee, Diesel Pushers & Caterpillar RV Engine Advisor

The Fridge Defender is the best aftermarket item sold today, it is truly a value for anyone with a Dometic or Norcold fridge. You will sleep better knowing such a quality product is helping protect your cooling unit and your safety. Phillip Enoch, RV Inspector & Technician
While in OH, we attended an RV Rally. As usual we leveled our RV, but the leverlers sank into the graound. The Fridge Defend prevented our referigerator from overheating due to being off-level. Thanks Paul & Mao for a great product! JVAndrews, Retired Aeronautical Engineer - USAF

1 2 3 4 5 6

Boiler Failure Root Cause Analysis Diagram

image/svg+xml Recall LP System Electrical Ventilation Slide-Out Maintenance Airflow Flat Tire Emergencies Parking Wear Tear Terrain Temperature Humidity Wind Leveling-Jack Environment Mountain Pass RV Operator Driving Contamination OVERHEATING BOILER Fridge Defend Failure Prevention Immeasurable $ Expense $ Fridge Fails Fridge Stops Cooling PROBLEM SOLUTION Fire
   TAP/CLICK any text in above diagram to read cause of boiler overheating.

Above is a 'Fishbone' diagram that Dometic and Norcold use to evaluate problems with their refrigerators. Please note that the top portions of the diagram are causes that the RV owner has no control over. The bottom is within the control of the operator. Both top and bottom issues are resolved by the Fridge Defend. At either end of the fishbones are the categories that engineers, field technicians, insurance underwriters, and customer reports indicate are sources of refrigerator failure. The categories are RV, Environment, Driving, and Operator. The bones for each of the categories lists causes of failure, and the line in the center (fish backbone) is the effect. To the right of the effect (fish head) is the failure that is being diagnosed (up = problem). This is a hybrid diagram because intervention of the failure is also included in the fish head (down = solution).


• Cause/Effect (fishbone) Objective

The objective of the fishbone diagram is to find the solution to failures once a failure mode is determined. Dometic and Norcold determined that overheating of the boiler results in failure and subsequent fires.

If Dometic and Norcold documents are not enough proof for you, then read the science described in US Patent 6,203,718 :
In summery: When the water in the system boils, the steam will not carry the sodium chromate inhibitor. Thus, high concentrations of inhibitor are within the boiler, and in the weak solution there is none, thus the failure of the fridge is imminent.


• Recalled & All New Dometic and Norcold Refrigerators

Dometic and Norcold recalls and subsequent fixes on new refrigerators only respond to overheating of the boiler after it has happened. The Fridge Defend is the only solution which prevents boiler overheating and the damage it causes.

HISTORY: RV refrigerator fires are not new. The industry has done a great job of suppressing the issue. One may ask why? It is simple, failures sell product, as a result the incentive is to allow failures to sell product at your risk.

Dometic Patent 1930: Even this early in Dometic history it is understood that the overheating of the boiler results in failure of the refrigerator!

Click here to read more history of RV fridge failures and fires.

Dometic Patent 1965: "Safe Operating Range" patent document quote "abnormally high elevated [boiler] temperatures tend to shorten the life of the refrigeration apparatus". Clearly Dometic acknowledges that high boiler temperatures can sell new refrigerators.

Dometic Patent 1980: "Such 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."

Norcold Recall 2002 & NO CO Patent: NHTSA issues recall due to fires. Find all of this hard to believe, then click here to read letter from Norcold to NHTSA ! Norcold files patent for the NO CO error codes. Rather than Norcold addressing the root cause, boiler overheating, Norcold addresses the symptom of the problem, fridge not cooling. Norcold decides that if after 2 hours the fridge does not cool, then turn off the fridge and issue NO CO error. In 2 hours your fridge can be destroyed if it does not produce refrigerant! But this may be the intention, who wants to fix a problem if one can profit from it? The Fridge Defend detects a 'no refrigerant' situation immediately, thus say goodbye to NO CO errors and hello to Fridge Defend!

Click here if you need to reset NO CO or Not Cooling fault or error codes.

Dometic Recall/Patent 2007: NHTSA Recall 06E-076: "containment system", why contain the fire? Why not deal with the root cause, the boiler overheating?

Norcold Recall 2010: Finding this to be incredible? Just click here to read letter from Norcold to Fridge Defend explaining what Norcold recall does. This NHTSA recall replaced 4, yes 4 previous recalls that did not get it right, and this one misses the mark as fires still occur to this day with the recall in place.

Click here if you need to reset Norcold black box HTS 634737.

Dometic Patent 2011: Dometic's own words to prevent: "Personal & Property Damage; Further Operation of Fridge; Fires & Explosions.", In other words, prevent you from using your refrigerator rather than addressing the root cause like the Fridge Defend does.

Dometic Recall Norcold Recall
Fires & Explosions Letter from Norcold Explaining Recall
VIDEO: Dometic Recall - How it Works VIDEO: Norcold 1200 Recall - How it Works
Dometic Recall in a Nutshell - What it Accomplishes VIDEO: Norcold 6xx, 8xx, & 1095 Recall - How it Works

Return to Cause-Effect Diagram

• Propane Gas Operation can Overheat Boiler

This is a classic paradox, when the boiler does not get enough heat, the boiler will overheat because the boiler pump cannot work. Causes of low heat at the boiler include LP regulator failure, plugged LP filter, and plugged gas jet. The Fridge Defend protects you from these kinds of failures.

Click here to see video showing how boiler overheats with low flame.

Click here to read how the Fridge Defend helped prevent a fire in a Norcold fridge with plugged LP system.

• Electrical System can Overheat Boiler

Electric heaters can cause the boiler to overheat in a number of ways. Here are just a few: One is low power to the heater, this results in low heat to the boiler, just as described for the LP System, low heat ultimately results in the boiler overheating. Another issue we see often, when the fridge has two heaters and one fails, this also causes the boiler to overheat. The Fridge Defend is a solution to these issues.

Click here for more on boiler overheating when electric heater fails.

• Ventilation can Overheat Boiler

Fridge Defend solves issues such as Wind Currents around your RV that can prevent air circulation when parked, especially at the beach.
Hot Weather that stops the cooling cycle, Fridge Defend will make fridge cool better by intervention and restart once cooled. Our Fridge Defend Kit #3 or #4 Fan Controller, see Testimonial "Wow - Cooled faster Colder".

• Fridge Side-Vents can Overheat Boiler

Click to read if your fridge is in Slide-Out or Side-Vents which have poor circulation.

• Leveling-Jacks can Overheat Boiler

The following two testimonies tell the whole story, one does not always know when they are level. Leveling jacks can sink into the ground or creeping down due to fluid leaks or air in the line, these are just a few issues that are common, the list goes on with things like binding and relay failures.

JVAndrews Aeronautical Engineer - USAF Testimonial

Lew King - RM1350, thank god I did not have a fire! .


• Wind can Overheat Boiler

As difficult as it is for one to comprehend, the wind blowing in just the right direction will result in what we coined ‘wind stagnation’ of the cooling unit ventilation. We feel it best let our customers do the talking, please see this IRV2 testimony:

Testimony on IRV2 forum on 'Wind Stagnation' by happy Fridge Defend user. .

• High Humidity can Overheat Boiler

It is true, in higher humidity the air conducts heat away from your fridge much slower. At first we could not explain why our fan controller Fridge Defend improved cooling so much in hot humid weather. It is counter intuitive, my reasoning was that humidity being water, it will conduct heat better, but this is just not true, use following link to read proof:

Click to see why humidity lowers the thermal conductivity of air. .

• High & Low Ambient Temperatures can Overheat Boiler

Hot Ambient Temperatures:

Is your fridge not performing in hot weather? Do you have a large fridge like a Dometic RM1350 or Norcold 1210 or 2118? Our customers are satisfied: Fridge and freezer are working 100% better now.

Freezing Ambient Temperatures:

In freezing weather the weak solution can freeze. In turn the boiler will overheat. In most cases Fridge Defend detects this condition, and will allow the fridge heater to thaw and automatically restart the fridge. Click here to see freezing weather fire in Dometic RV Fridge  and  Click here to see freezing weather Testimony .


• Driving, Terrain, & Mountain Pass can Overheat Boiler

Terrain and Mountain Pass are the same failure mode. We combined them into one type of failure cause because of the many reasons for this type of failure.

Terrain: One of the common issues that results in overheating is RVs seeking the great camp sites on dirt roads. Moving slowly in the dirt and climbing steep hills to those great camp sites with the view will overheat your boiler.

Mountain Pass:

Events like climbing or descending long steep hills that cause slow but cumulative damage.

Note the verbiage in Norcold N4151 operators manual, "performance during travel is not usually affected", click to read testimonial about this subject.

Click here to see video at top of this page of climbing Mountain Springs I-8, California.

• Ware & Tear -- The Natural Aging Process Accelerated by Overheating

The Fridge Defend solves the root-cause resulting in the failure of these otherwise great refrigerators.

The primary root-cause of RV fridge failure that leads to fires is the overheating of the boiler. Dometic and Norcold did the analysis, clearly overheating promotes corrosion and in turn reduces service life of the fridge.

This video shows a boiler rust pit measured by a Leica Electron Microscope. The microscope calculates the rust pit as being what caused the failure that lead to a fire in this fridge. Science presents the facts, no argument here! Cause of fire, just as Dometic and Norcold state in their documents, damage from overheated boiler.

Click to see the same boiler as seen in this video used to make Dometic & Norcold Agree video.

• Contamination can Overheat Boiler

The cooling unit compartment can have things like insulation fall down and block the circulation needed for safe operation. Another problem is animals and insects making their home in the cooling unit compartment. Yet another is leaves and even trash introduced into the cooling unit compartment that prevents circulation of air, without proper air circulation the boiler overheats.

Click to view photo of cooling unit that was destroyed by cottonwood seed contamination.

• Flat Tires or other Emergencies

These categories are really not in the control of the refrigerator operator, even if the RV industry would like to think so. No one chooses to have a flat tire or a break down that requires towing. Would you choose to go to the emergency room? Yet, these are come of the most common causes of boiler overheating that result in fridge failures and eventually fires.

Click to read Bob Livingston’s testimonial about experiencing flat tires.

Click for Towing RV and Fridge Protection due to highway breakdown.

Medical emergency testimonial.

• Airflow while Driving

Dometic and Norcold Facts
Driving or parked - the wind is the same; the difference is that driving adds a new direction to the wind. Your vehicle has to separate (displace) the air in order to move through it. The result is that your vehicle produces eddies and vertices, fluid science calls this turbulent flow. The result is that your cooling unit cannot reject the heat that is required for proper operation which results in boiler overheating.

Each vehicle is different in the way air flows around it. Our RV, when the wind is at a 45 degree angle to the front of our vehicle, coming from the drivers side, our boiler overheats.

Cross winds that prevent air flow in cooling unit compartment driving down the road.


• RV Maintenance

See: RV Repair Shop Proceeded to jack up RV and work on it.

• Parking

Click to see a classic photo of RV parked off-level in Quartzsite, AZ.


Fridge Stops Cooling (the result of boiler overheating)

Not only does your fridge stop cooling because no refrigerant is being produced, the long term effect is your fridge cannot cool due to the breakdown of the rust inhibitor. " Nitrogen gas is the primary non-condensable gas formed in chromate-inhibited systems. In chromate-inhibited systems, the rates of magnetite scale formation and chromate breakdown increase with increasing temperature ". Which could have all been preveed by the Fridge Defend® US Patent 8,056,360 .

Doubting? Ask yourself why does Dometic and Norcold say " it is of paramount importance that this heat is kept within the necessary limits and is properly applied. "

Click here to see video and explanation of why your RV fridge fails due to overheating of the boiler.

OLD: Click here to see (older) video and explanation of why the fridge fails.


Fridge Fails (the result of allowing boiler to continue overheating)

Please reference Department of Energy US Patent 6,632,294, where it is stated that " sodium chromate is effective for operating temperatures up to about 200°C ". Thus, the effect is slow but cumulative damage and loss of cooling due to the breakdown of " sodium chromate which can react with ammonia at high temperatures to form nitrogen gas and sodium hydroxide (caustic soda) ".

Doubting the science in the above patents from the Department of Energy? Then ask yourself why Norcold states "Preventing the boiler from operating at high temperatures can avoid consumption of sodium chromate ".

Click here to see video and explanation of why the fridge fails.

OLD: Click here to see (older) video and explanation of why the fridge fails.


Fire (the result of failure)

Doubting? Click here to see what Dometic and Norcold say about their refrigerators.

Click here to see video and explanation of why the fridge fails.

OLD: Click here to see (older) video and explanation of why the fridge fails.


Fridge Defend (patented solution)

Dometic and Norcold confirm via documentation that the Fridge Defend is the only solution to all the causes of RV fridge failure in the fishbone diagram.

Unfortunately, Manufacturers' recalls only respond to overheating of the boiler after it has happened, which is confirmed by the Dometic and Norcold documentation.
The Fridge Defend is the only solution which prevents boiler overheating and the damage it causes.
No other recall or method can make this claim because the Fridge Defend is patented & meets international safety standards.

Click here for Fire Photo Top of this Page

Dometic and Norcold Fridge Defend Basic or Fan Controller
Fridge Defend by ARP Rated
4.8 stars based on 155 customer reviews

What Products are Offered by ARPC LLC?

Product Description: We have two models of controller, the Basic Fridge Defend & Fridge Defend + Fan Control. Both controls protect the cooling unit by monitoring the boiler temperature. The Fridge Defend + Fan Control has an an additional fan controller which improves the fridge efficiency. Fridge Defend products range in price from $147.50 to $225.00

Please click here to go to our customer review/rating page.

Fridge Defend by ARP Improves Safety, Reliability, and Efficiency


★ ★ ★ ★ ★


Winnebago Sightseer 35N - 2006

ARP + Fan Control

Star Rating: Super great service. Paul went out of his way help me while I installed the ARP Basic unit in a friends Class A motor home. I installed an ARP with fan control in my Class A MH. I just love how the Fan Control has improved the cooling in my Norcold.

So what is up with the bar graphs and the testimony from LaPlatrosa?
Out of the total number of customer ratings, these graphs show how many people that bought the Fridge Defend by ARP and felt that their family was safer, their fridge was more reliable, and that the ARP + Fan Control made their fridge more efficient. Please note that none of the pets that were left alone in the RV reported , but an independent survey (the dog next door) stated that 100% of pets insist their master is goofy if they do not purchase a Fridge Defend by ARP Control for safety. LaPlatrosa left this review of the ARP Control on 9/5/2015, we love Happy Campers!

Please Click Here for more Testimonials  & See these comments from the Grand Design Owners Forum

Escapees Gadget Box Supports ARP Control

Please click image to left to see RV Gadget Box article from Escapees magazine, May/June 2014. Reprint courtesy of Escapees RV Club.

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

Please click here for RV Gadget Box article May 2017

Please click here for Mark My Words Good Sam Club Blog

Escapees Magazine Article — Your RV Refrigerator
• Part 1 How it Works like Salt and Moonshine?
• Part 2 LP Gas Operation
• Part 3 Electric Operation
• Part 4 Controllers and Recalls
• Part 5 Removing the Heat
• Part 6 Inside Your Fridge
Click Here for Door Seals

• Part 7 Replacing Dometic or Norcold Cooling Units
Click Here for Cooling Unit Replacement Video Series

Click Here for National RV Refrigeration

• Part 8 Oil Contamination in LP Gas Systems
Click Here for LP Gas Safety Video

Click Here for Filter Cleaning & Pressure Test Video

Stop RV refrigerator fires before they start!

Click here to see this article by Russ and Tiña De Maris about stopping refrigerator fires

Revised RV refrigerator safety device protects against fires

Click here for Press Release on v5.x Fridge Defend

Refrigerator fire ruins the whole day

Photos that bring that truth home - Fire event happened because of the fridge over heating

Refrigerator failure: Replace or repair?

Fridge Defender to prevent fires and extend the life of our RV Refrigerators

Do you really need a new refrigerator?

Click here to see article by Russ and Tiña De Maris about replacing their cooling unit

Nordic Cooling Units -- Cooling Unit Used in Above Article

Click here for Nordic Cooling Units

Escapees RV Club Supports ARP Control

We are pleased to be Escapees members. Escapees club is an advocate for all RV'ers, they truly care for the welfare of their members.


Fridge Defend by ARP and other high quality RV vendors supported by Escapees.

RV Forum

The friendliest place on the web for anyone with an RV or an interest in RVing.

Click here for "Another Cooling Unit -- Saved us from more serious problems, like a cooling unit fire"
Click Fridge Defend Home

We are pleased to be FMCA commercial members.

See Brett Wolfe, FMCA Technical Advisory Committee, testimonial above. Click here to see FMCA blog Fridge Defend by ARP Control - "we believe the ARP provides the best level of safety against potential refrigerator fires".


We support IRV2, and the participants of IRV2 support us, click here for very informative video on RV fridge fires!

• Will My RV Refrigerator Catch Fire, And Can I Prevent It?

Faraday Chiller • How Heat Makes Cold: How The Absorption Refrigerator In Your RV Works

• Is It Safe To Use My RV Fridge While Driving?

Tom Alexander RV Advisor

For the best Podcast - keeping you up to date on the latest RV information, click here and listen to our Fridge Defend interview on 10/7/2019.

Click here and listen to our Fridge Defend interview on 11/17/2020 via Facebook.

Click here and listen to our Fridge Defend interview on 11/17/2020 via YouTube.

Click here and view to our Fridge Defend interview on 05/12/2022 via Facebook.


The ARP Control introduces an improved method for protecting your Norcold or Dometic fridge while maintaining the original warranty ( Further reading see Magnuson-Moss Warranty Act ). The Fridge Defend pro-actively protects your fridge rather than responding after a failure has occurred such as the present recalls do. This is an improvement upon factory control methods, thus Magnuson–Moss Warranty Act insures that you can improve your safety. ( Also see: Restore Factory Settings )