Dometic Refer Recall - Possible Fire Hazard -Update 2/13/07

[MELM]

Click here to go directly to Updates.
Update Number 1 Nov 23, 2006
Update Number 2 Dec 5, 2006
Update Number 3 Jan 10, 2007
Update Number 4 Jan 19, 2007 - Recall Instructions - click here: Dometic Recall You need your model and serial numbers.
Update Number 5 Feb 13, 2007 - Added links to new info on the NHTSA website including the info/form for claiming reimbursement for a failure. These are at the end of the post below where all the updates are posted.

Also, edited the below Recall to include the change made prior to the Dec 5 update showing the proposed remedy.

Below is information from the NHTSA website on a recall of certain Dometic refrigerators. This recall is in its very early stages, and there is no resolution in place as of Nov 1, 2006.

From the NHTSA website:

Dometic Recall NHTSA Campaign ID 06E076000

Make / Models : Model/Build Years:
DOMETIC / NDR1062 9999
DOMETIC / RM2652 9999
DOMETIC / RM2662 9999
DOMETIC / RM2663 9999
DOMETIC / RM2852 9999
DOMETIC / RM2862 9999
DOMETIC / RM3662 9999
DOMETIC / RM3663 9999
DOMETIC / RM3862 9999
DOMETIC / RM3863 9999

Manufacturer : DOMETIC CORPORATION

NHTSA CAMPAIGN ID Number : 06E076000 Mfg's Report Date : AUG 28, 2006

Component: EQUIPMENT: RECREATIONAL VEHICLE

Potential Number Of Units Affected : 926877

Summary:
CERTAIN DOMETIC TWO-DOOR REFRIGERATORS MANUFACTURED BETWEEN APRIL 1997 AND MAY 2003: SERIAL NOS.
713XXXXX THROUGH 752XXXXX;
801XXXXX THROUGH 852XXXXX;
901XXXXX THROUGH 952XXXXX;
001XXXXX THROUGH 052XXXXX;
101XXXXX THROUGH 152XXXXX;
201XXXXX THROUGH 252XXXXX;
301XXXXX THROUGH 319XXXXX,
INSTALLED IN CERTAIN RECREATIONAL VEHICLES AS ORIGINAL EQUIPMENT AND SOLD AS AFTERMARKET EQUIPMENT. A FATIGUE CRACK MAY DEVELOP IN THE BOILER TUBE WHICH MAY RELEASE A SUFFICIENT AMOUNT OF PRESSURIZED COOLANT SOLUTION INTO AN AREA WHERE AN IGNITION SOURCE (GAS FLAME) IS PRESENT.

Consequence:
THE RELEASE OF COOLANT UNDER CERTAIN CONDITIONS COULD IGNITE AND RESULT IN A FIRE.

Remedy:
THE VEHICLE MANUFACTURERS WILL NOTIFY OWNERS OF RECREATIONAL VEHICLES THAT HAD THE REFRIGERATORS INSTALLED AS ORIGINAL EQUIPMENT AND DOMETIC WILL NOTIFY OWNERS OF THE AFTERMARKET REFRIGERATORS. DOMETIC WILL INSTALL A SECONDARY BURNER HOUSING FREE OF CHARGE. THE RECALL IS EXPECTED TO BEGIN BETWEEN APRIL AND JUNE 2007. OWNERS MAY CONTACT DOMETIC AT 888-446-5157.

Notes:
CUSTOMERS MAY CONTACT THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION'S VEHICLE SAFETY HOTLINE AT 1-888-327-4236 (TTY: 1-800-424-9153); OR GO TO HTTP://WWW.SAFERCAR.GOV.

The following is extracted from the notice provided by Dometic to the NHTSA dated 8/26/06:

The potential defect is associated with cooling unit at the back of the refrigeration cabinet.

A fractional percentage of the potentially affected refrigerators have experienced a fatigue crack that may develop in the boiler tube in the area of the weld between the boiler tube and the heater pocket. A fatigue crack may release a sufficient amount of pressurized coolant solution into an area where an ignition source (gas flame) is present. Dometic's investigation has shown that a simulated release of cooling solution (refrigerant) in the area of the boiler, under certain conditions, could be ignited by the presence of an open flame. A boiler fatigue crack with the loss of cooling solution without ignition would result in a non-operational refrigerator that is not a safety issue. Under certain conditions, the released coolant could ignite and result in a fire. In order to have a fire, at a minimum, all of the following conditions must exist:

1. The refrigerator must be on and normally operating and gas burner must be lit;
2. 'There must be an oversized heating element in the refrigerator;
3. The boiler tube must develop a throughway fatigue crack of a
specific size;
4. There must be a release of the cooling solution at a rate which will
allow the accumulation of the cooling solution at a concentration within its range of flammability; and
5. There must be ignition source (gas flame) present.

If any of these conditions are not present, a release of the cooling solution will not result in a fire.

In April of 1997 Dometic modified the design of the affected refrigerators by increasing the wattage of the heating element from 325 watts to 354 watts. All production of the affected units from April 1997 through May of 2003 utilized the 354 watt heating element. In May of 2003, in order to improve the operating life of the refrigerators, Dometic returned to the use of the 325 watt heating element which it continues to use today. It is now believed that the use of the higher wattage heater contributed to abnormal fatigue in the boiler tube.

The products in question are all refrigerators used in the original manufacture of recreation vehicles or as replacement equipment for recreation vehicles. The total population of refrigerators potentially containing the defect is 926,877. Dometic estimates a potential maximum incident rate of 0.01% related to boiler fatigue cracks that leak and may result in a fire. There have been no incidents of injury or death related to the affected population of Dometic refrigerators.

Dometic became aware of the occurrence of fires which may have involved their products and retained an independent engineering testing laboratory to fully evaluate and investigate any potential defect in their refrigerators which might result in a fire. A number of returned units were analyzed and microscopic fatigue cracks which could release coolant into the area of the burner were identified in the boiler tube metal in the area of the weld between the heater pocket and boiler tube. Tests simulating the cracks were conducted the week of August 18, 2006 and confirmed a possible cause of fire in the refrigerators under certain conditions. These test results prompted the preparation of this notice.

Dometic continues to gather information on the potential defect and will forward additional relevant information as it becomes available.

Dometic has not yet identified a proposed remedy for the potential defect. Dometic will continue a testing program designed to identify and evaluate possible remedies. This evaluation will take place both in the United States and in Sweden. Once a remedy has been identified, Dometic will initiate or participate in a remedy campaign initiated by the original equipment manufacturers and aftermarket suppliers who have purchased, sold, and distributed these products. A list of original equipment manufacturers and aftermarket suppliers to whom Dometic has sold the potentially defective refrigerators is being prepared and will be provided to the NHTSA upon its
completion.

The following is extracted from the NHTSA response on 9/18/06:

Please provide the following additional information and be reminded of the following requirements:

Dometic must provide an estimated dealer notification date as well as an owner notification date including the day, month, and year. You are required to submit a draft owner notification letter to this office no less than five days prior to mailing it to the customers. Also, copies of all notices, bulletins, dealer notifications, and other communications that relate to this recall, including a copy of the final owner notification letter and any subsequent owner follow-up notification letter(s), are required to be submitted to this office no later than 5 days after they are originally sent (if they are sent to more than one manufacturer, distributor, dealer, or purchaser/owner).

Dometic must file a sample of the envelope which you intend to use to mail the recall notice to owners. The words "SAFETY", "RECALL", "NOTICE" in any order must be printed on the envelope in larger font than the customers name and address.

[WilleyB]

Hi LScamper No apology necessary, my own terminology could use a bit of correcting. If my post looks a bit aggressive, I apologize, it was not meant to be. This transformer idea was your's alone and it is a good one. If I had of thought about it first, I'd have used it instead of buying a new element.
We are a bit down in the chin around our home as our dog of 12 years passed away last Tuesday so I'm not my usual self. I guess I'd better redo that drawing so as to better represent a RS transformer with a more correct description.
Willis

[LScamper]

Sorry Willis, I should have stayed with my original terminology that is a buck transformer. They work almost the same as an autotransformer.

One small advantage to the buck transformer configuation is that the secondary winding does not have to be connected to the primary at the transformer. You can plug in the primary to the 115 AC and connect the 6V or 12V secondary in series with one line of the heating element. Just make sure it is bucking not aiding.

Once again sorry I used autransformer in my last reply.

[WilleyB]

The autotransformer is a good solution but expensive. My sugestion on using the Radio Shack transformer is a cheap method of building an autotransformer.

Uh! that's what my diagram was all about a "Radio Shack transformer"
If only the 120/ 12 volt txfmr is available then the center tap of the 12 volt winding and one of its other leads can be connected as shown. Since they share the same core it can be wired as an auto transformer.

Circuit City Transformer

Willis

[LScamper]

I'll reply to two posts here.

The rheostat idea will work fine but like you said it will get hot and should not be in the area behind the refridge. The autotransformer is a good solution but expensive. My sugestion on using the Radio Shack transformer is a cheap method of building an autotransformer.

The 600 watt dimmer should work great as long it is wired only to the heating element as you have done. The only problems maybe noise in AM radios and the voltage you measure may not be correct. If you have a standard digital voltmeter the reading will not be correct (it maybe close, the higher the dimmer setting the more accurate the reading will be). If you have a true RMS voltmeter the reading should be correct.

I may try the 600 watt dimmer methode.

[Frank_mar]

I have two refrigerators operating using DIMMER switches. The Dimmers are rated for 600 watts which is way more than the 325 to 400 watts required for the heating element.
One fridge has been running for 3 weeks without any problems. Both heating elements were measured at 37 ohms, and we have been operating the power thru the Dimmer at 110 volts. With an incoming voltage of 122 volts, I can adjust the heating element voltage as low as 85 volts or as high as 122 volts. I have had no problem with measuring voltage using a digital voltmeter. Also, the fridges having been working just fine on the same setting as before without the dimmer.
The dimmer cost me less than $5.00 at home depot.
The Dimmer is mounted in a metal outlet box with an outlet installed for plugging the element into( adated the two element wires to a plug) and the other socket for measuring
voltage.
Frank

[CrossCountryNom]

LScamper wrote:
A dimmer chops up the power 120 times a second. With some bulbs you can hear them vibrate as the power goes on and off...

I think you are referring to an electronic/solid state dimmer here. Others have made references to an autotranformer or a rheostat that can can be adjusted to the voltage you need with most common voltmeters. Rheostats have been around since day one in the electrical world and where some of the first types of dimmers available. Typically a rheostat can handle fair amounts of current. A rheostat's drawback is that it will generate heat as the voltage/load changes.

[LScamper]

Using a dimmer sounds like an easy answer to the heating element problem. There are some things to think about before using one. First an understanding of how a dimmer works is in order. This explanation is far from complete but should be good enough for now. A dimmer chops up the power 120 times a second. With some bulbs you can hear them vibrate as the power goes on and off. To change the brightness of a light bulb the chopped power is turned on and off for various lengths of time. To make it bright the power is on most of the time. To make it half bright the power is only on about half the time. To make it dim the power is off most of the time. This works great for light bulbs and will work for the heating element in the refrigerator.

The problems come in when you try to run other equipment on this type of power. One problem is that it generates a lot of electrical noise that you can hear in an AM radio. Transformers and power supplies will not work correctly and may overheat and burn out. Relays will not work sometimes. The biggest problem comes from measuring the voltage. Most voltmeters will not read the correct voltage when measuring this type of voltage. Some special meters will. If you cannot measure the voltage you cannot set it to the value you want to produce the desired power level for the heating element.

For the above reasons I would not try to use a dimmer for this application.

[Claude_B]

Would it be more easier to just add a dimmer so what ever you have in the CG (110, 115, 120 V) you can adjust in consequence ?

[LScamper]

The autotransformer will work fine. I was thinking the opposite configuration. Put the 120V where you have the 113V and wire the 6.3V as buck voltage. Either configuration will work fine! The Radio Shack transformer should work but watch the current rating it is 3A. Maybe two of these transformers in parallel would give almost 100% safety margin.
Thanks for the picture.

[dcarpenter252]

timsrv wrote:

Claude B wrote:
I think the only reason why Dometic include a thermal cut off in their kit is to cut the power (12 V & 120V & gas) in case of a boiler tube failiure.

Yes, I agree, by what is the fusible link inside the sheet metal housing for? is it there to cut power during a flash fire, or to cut power if the element draws too much power? Tim

The fuseable link is to kill power in case of fire. It is connected in series with the thermodisc in the DC power line.
Hope this helps.
Dennis

[WilleyB]

Hmm! perhaps you're thinking autotransformer which will work fine. A transformer connected as you suggest will also work fine as long as the current requirements of the element and transformer capability's are respected.
My humble efforts Click-->
Now the key here will be the leads of the 6.3volt winding. In series aiding you will get 113.7 volts output for the element, however by reversing the the lead connections it would give a BUCK situation which would further decrease the voltage to the element.

So in the AIDING situation where you'd get 113.7 VAC for the element, a 40 ohm element would dissipate 323.2 watts, that's close enough.

Willis

[LScamper]

Think outside the box. It seems that a lot of people feel unsafe with a heating element that is more than 325 Watts, 40 Ohms at 115 Volts and would like to replace it. They seem to have a problem getting a replacement element that is in this spec. Instead of replacing the element (which is expensive) why not lower the voltage the required amount to use their heating element at the 325 Watts they want?

This is easy to do by using a circuit element called a buck transformer. The idea is to subtract a voltage from the 115 VAC to lower it the amount necessary so the heating element is producing 325 Watts. First calculate the voltage needed. (Use your measured heating element resistance)

For a 40 Ohm ideal element:
Eneeded = square root of Power x Resistance
Eneeded = square root of 325 Watts x 40.7 Ohms
Eneeded = 115V

Find the voltage needed to subtract using a transformer:
Etransformer = Esource – Eneeded
Etransformer = 115V - 115V
Etransformer = 0V, nothing needed!

For a 36 Ohm element:
Eneeded = square root of 325 Watts x 36 Ohms
Eneeded = 108 Volts

Find the voltage needed to subtract using a transformer:
Etransformer = Esource – Eneeded
Etransformer = 115V = 108V
Etransformer = 7V

If you want to use 120 Volts in your calcultations:
For a 36 Ohm element:
Eneeded = square root of 325 Watts x 36 Ohms
Eneeded = 108 Volts

Find the voltage needed to subtract using a transformer:
Etransformer = Esource – Eneeded
Etransformer = 120V = 108V
Etransformer = 12V

Next find the current rating needed for the transformer:
I = E/R
I = 108Eneeded / 36 Ohms
I = 3 Amps

So in this case you need a transformer rated at 12 Volts at 3 Amps.
Radio Shack has one catalog number 273-1511 rated at 12.6 Volts at 3 Amps for $10.49. This transformer also has a 6.3 V output if you need just 6 Volts.

Maybe someone can draw a picture of how to hook it up. The idea is to hook up the 115 volt winding to the 115 Volts and hook the secondary side (6.3 V or 12.6 V) in series with the 115 Volts so that it reduces the voltage. If it increases the voltage reverse the secondary winding wires. This will allow your 36 Ohms element to operate at 325 Watts instead of 365 Watts. This may be easier and cheaper to do that trying to get a new element.

[Claude_B]

Tim, I agree

[timsrv]

Claude B wrote:
I think the only reason why Dometic include a thermal cut off in their kit is to cut the power (12 V & 120V & gas) in case of a boiler tube failiure.

Yes, I agree, by what is the fusible link inside the sheet metal housing for? is it there to cut power during a flash fire, or to cut power if the element draws too much power? Tim

[Claude_B]

I think the only reason why Dometic include a thermal cut off in their kit is to cut the power (12 V & 120V & gas) in case of a boiler tube failiure. We all all know that in a boiler failure, there is no more heat transfer and the temp goes up and up and could be a fire hazard. Dometic is only saving their a.. in case of a law suit and they don't care to solve the root cause of the problem by replacing the 350W + heating element. And if there is only one element, I would ask the Dometic guy why the recall is only for the 1997 to 2003 models ?