โNov-01-2006 05:30 PM
โMar-07-2007 05:48 AM
โMar-07-2007 05:36 AM
โMar-07-2007 01:04 AM
โMar-06-2007 11:20 PM
โMar-06-2007 05:50 PM
โMar-06-2007 12:36 PM
I can't figure out how they get 41 ohms, 325 watts, 120 volts and 2.7 amps. Would they have a typo on 2 product sheets?
If that 41 ohms is right, 10% less is 36.9 ohms.
My element is 43.9 ohms So I'm set there, but I do not have the high temp cut off. Will add in the future.Right on, I guess we're both at the same stage now, wait for the fix and add the hi temp cut off. I's possible we may have to wait for spring then fire it up to find what the operating temperature is, then add an increase factor to take care of false alarms.
โMar-06-2007 09:58 AM
โMar-06-2007 07:56 AM
rsg33 wrote:
The unit is LP/110V only. Dometic uses the same cooling unit (with two pockets) for the two-way and three-way double-door fridges. I'll get closer shots when the cooling unit is removed from the box tomorrow.
The main thing to note is the element is NOT a 354W and has never been changed, so I'm not sure about the validity of the higher wattage/over-heating issue. It appears, judging by this unit, that a defect can show up even with the standard 325W element.
โMar-06-2007 06:41 AM
Shangrila7 wrote:
I just received my recall notice today and was kind of concerned.
But...then I read on this forum where a chance of fire is only .01% of the 993,000 suspect units built over the last 10 years?
I've no facts but, I'd guess that the heaters, stoves, ovens, propane systems, stereos, etc., etc., in Rv's have design flaws that have not been disclosed and are of equal to or greater of a fire danger than what dometic has disclosed. Due to as lawsuit happy as this country is, Dometic is only trying to protect itself. 2 or 3 mega law suits would put them out of business. If this situation was as serious as some perceive, it would be all over TV, radio and the newspapers.
If there has been no injuries, deaths or lawsuits over the last ten years due to these suspect units, we should be more concerned about the spinach and peanut butter we consume. If the gas prices continue to climb, I won't be even using my RV that contains my dangerous dometic fridge.:)
โMar-05-2007 08:15 PM
โMar-05-2007 07:26 PM
rsg33 wrote:
A couple of you wanted pictures. This is a classic recall case. The first pic is what the owner saw from the exterior. The second is of the perc area with the insulation and outer housing removed. It's hard to tell exactly where the leak originated, but I suspect at the common weld between the 12V pocket and the 110V pocket. I'll know better when the cooling unit is actually removed from the box.
This is a RM3862 out of a 2002 5th and is on the recall list. The element is marked 115V-325W. Part # 173768-03 The ohms will be checked tomorrow and I'll edit this post with the reading. Dometic has supplied a new cooling unit and will warrant this defect for the owner.
โMar-05-2007 07:04 PM
WilleyB
Snip..
Hi John, while reviewing the thread there's little doubt in my mind that the culprit is two fold. I do believe between Dometic's recall paper, only fridges with the underrated element (354w???),Tim's post about the common factors to the failures was the underrated heating element and that it failed at the first weld above the elbow, plus Chris' post on the effect of stress from heating the weld.
Willis, I agree this is a multi part problem where the right conditions have to add up. And I can see a cyclic thermal expansion problem adds up with the higher wattage element. Without a real good picture of how the element is placed in relation to the crack and the metal thickness around it, I can't add much more science to this. If we do not come up with a pic soon, I may find out on my own.
A big question in my mind "Why such a low failure rate?"
There's also no doubt in my mind that a lot of failures happened but for reasons unknown (not reported)are not included in the statistics. Yet there's much reason to believe the failure rate is still low.
Yes I agree with this too. Unless someone knows of the problem, this could be just written off for road vibrations, or a weak unit. Tim, helped make it clear that his failures where not even on the road.
Now here it gets kind of iffy, Chris most likely could explain this better.
Those who have welding experience will understand there is a quality of weld depending on the penetration (mix of new metal to the pieces being welded)when heated the stress characteristics of this welded joint are quite different to the surrounding metals. It's easy to believe that a lower number units might have a much deeper weld penetration than the rest (new or novice welder)and when overworked by an excessive expansion and contraction, the weld will break from from one of the metals that were joined leaving a very weak structure.
Yes, there is merit in this as well. Running mostly on propane would create a different situation than those running mainly on electric. And then there is weld quality
No matter which parts list you look at the parameters for a 325 watt element is 44 ohms +/- 10% if your fridge has that it's not on the recall list. There is a reason for this, an absorption refrigerator must have the correct heat to operate. The low end tolerance is 39.6 ohms, so it is safe to assume this would generate the hottest allowable temperature and the expansion and contraction factor does not overwork the weld.
Well there are different ratings.
Look at this RM 2620 it is listed as 48 ohms and 295 watts. See page 2
And here is a RM2663 with 41 ohms and 325 watts. See page 2 RM 2663
If that 41 ohms is right, 10% less is 36.9 ohms.
I can't figure out how they get 41 ohms, 325 watts, 120 volts and 2.7 amps. Would they have a typo on 2 product sheets?
The Dometic modification to the best of my knowledge, from what is posted on this thread, consists of a fix so that the unit does not catch fire when the cooling unit fails while operation on LP gas.
So What to do. I don't know about anyone else but here's my reaction.
1 Replace the heating element with a new one of correct specifications (preventative, why push one's luck)
2 When the Dometic fix is ready, have that done (Safety, it's free why take a chance)
3 When we have enough information I will install the thermal cutoff. (more safety, it's easy to do so why not)
Because of the thread I believe we have a better understanding of the problem and remedial actions we might take. At least now when we go out for a run I'll feel a lot better about it all than when the thread first started.
Cheers Willis
โMar-05-2007 07:02 PM
โMar-05-2007 02:20 PM
โMar-05-2007 12:36 PM
Chris Bryant wrote:
This is the "gotcha" in this whole fiasco- I have never seen a published heating element resistance figure other than the 44 ohms- which is supposed to be measured every year in the required maintenance.
The only 38 ohms units I have run across were in units which the maintenance had not been done, but were still in the 3 year window.
I went ahead and warrantied them but charged for a new element, but I don't know what Dometic would have said if I had done the maintenance and turned in a 38 ohm heater.