RE: New Dometic Recall Initiated March 11, 2008
Yes, your experience is very common. Most units will never develop dangerous stress patterns, but a higher ratio than what we consider normal will. I don't know the exact numbers, but lets say that prior to the recall, maybe .1% of refers failed in this manner (this is a guess). Out of all the recall units, perhaps 10% will end up with cracked boilers (another guess). This means most recalled refers will not fail due to a cracked boiler, but many more than normal will. The odds are very very slim that any of your units will go up in flames. In order for that to happen, a crack needs to occur while running it on gas. In addition to this, the temp needs to be sufficient to make the ammonia flammable, in addition the crack needs to be the correct size to sustain the correct volume of ammonia / hydrogen, and also be directing it into the flame area. If I understand correctly what Dometic has published on the matter, the odds of having your boiler break, then have it be followed by a fire are about .01% (that's one one hundredth of one percent). Of course you have to wonder whether or not they have a biased opinion.
That being said, a risk of fire is still a risk most people don't want to take (no matter how small), and I don't blame them. As stated earlier, the recall kit does nothing to prevent the boiler from breaking. It's only intended to contain a fire should one occur. Still, even with the recall IMO there is still some danger. Hydrogen is an active molecule and it's conceivable it could wick out through the fiber glass in the flue area and burn in another location (not likely, but conceivable). I don't have any hard evidence to back this up, but I have seen hydrogen burn before. Let's just hope the folks at Dometic know what they are doing this time. I say "lets hope" because they obviously dropped the ball on building a safe and reliable cooling core. Tim
RE: New Dometic Recall Initiated March 11, 2008
It's been my observation that most refers that break boilers run mostly on electric. However, according to Dometic, a flame needs to be present for it to go up in flames. So for that reason, it's safer to limit refer operation to electric (running it exclusively on electric increases the chance of breakage, but limits the chance of fire).
It's my understanding that the ones that have burned developed stress patterns while running on electric, then finally broke while running on gas. Stress patterns are the areas that become overworked as a result of expansion and contraction. Once these patterns are set, these overworked areas will continue to flex more regardless of operation mode(and BTW there's no practical way to tell if you have stress patterns or not). So even if you stopped running it on electric and started using it on gas only, these stressed areas will still flex more then the unstressed areas because they are in a weakened state. If your refer has only been run on gas, then it most likely won't have these stress patterns and it's much less likely to break. It's the ones that run all the time on electric that I see failing. Tim
RE: New Dometic Recall Initiated March 11, 2008
Yeah, actually the life expectancy or a modern refer core (without this defect) is 12 - 15 years. With these recall units, many of my customers have had failures around the 2 year range. Usually it's a full timer that runs the refer 24/7 on electric only. One of my customers had 4 boiler tube failures before the 1st recall was even announced! Tim
RE: New Dometic Recall Initiated March 11, 2008
The build year is in the serial number- the first number is the year, the second two numbers are the week, so a serial number of 42600015 is the 15th refrigerator built in the 26th week of 2004.
..........or 1994:). Since the recall covers so many years, this has been a point of confusion. You'd think they would have put 2 digits there to indicate year. Oh well, not such a big deal I guess. It's not like any of these things will last a whole 10 years anyhow :S.
By the way, it's illegal to charge the end customer money to perform a recall. They are not required to reimburse you for travel and lodging, but they could be fined $15,000 if they get caught billing you for the install. Charging you a service call to come out is a gray area, I'm not sure if charging for that is allowed or not. Tim
RE: New Dometic Recall Initiated March 11, 2008
ssandee, I don't recommend you try yourself & I definitely don't recommend using a rebuilt cooling unit. The job isn't impossible but there are details to the job that can render your refer innefficient or completely useless unless performed correctly. As for the core, you might luck out and get a good rebuilt one, but it's been my experience they usually don't last very long. The longevity greatly depends on the ethics and thoroughness of the rebuilder. IMO replacing with a new cooling unit would be the better choice, however cost is almost as high as a new refer, and unless you achieve a near perfect fit, the refer efficiency will be compromised. Maybe it's time for a new Norcold?
shamon, I'm sorry to hear of your misfortune & hope nobody was injured. If you haven't already done so, I recommend you find a good lawyer. If you hire one on a contingency basis, it won't cost you a dime (initially). He will only get paid if he wins..........but will take about 1/3 of the award. Good luck. Tim
RE: New Dometic Recall Initiated March 11, 2008
Why doesn't this surprise me. I didn't think there was any difference between the earlier refers and these later ones........so why didn't Dometic just recall all at once? It seems to me they are playing a game. I'm a dealer and thanks to this forum I'm just now finding out about this. Dometic didn't bother to notify me about this new extension of the recall. I wonder who else they "forgot" to notify? IMO, this band-aid fix doesn't necessarily make the refer safe. Hydrogen is an active molecule and it's conceivable that fires can burn in other places like out through the stack. Tim
RE: Dometic Refer Recall - Possible Fire Hazard -Update 2/13/07
Just curious- what are the first 3 digits of the serial number (and entire model number)?
The reason I ask is that the Dometic serial numbers use the first three digits for the date- 1st digit is year, second 2 are week.
The RM2652 has just passed 10 years of manufacture, but they changed the model to DM2652 to avoid S/N mixups.
This true, However I believe some of the refers made early in 2007 still had the RM numbers and duplicate S/N of some of the 1st effected by the recall. I could be wrong about this, but I seem to remember seeing one or two that actually showed up as being effected (even though they were manufactured 4 years after the last recall refers). Needless to say, it was a bit confusing. The thing that made me disregard was that I seriously doubted they would put a 10 year old refer in a brand new coach. Tim
RE: Adding a second 12v chassis battery, wiring ???
When batteries are wired together they really should be of the same type, size, and age. You can wire together for a short term advantage, but over the long term (unless the above conditions are met), it can lead to premature failure of one or both batteries. Tim
RE: Dometic Refer Recall - Possible Fire Hazard -Update 2/13/07
Yeah, this refer showed below was used only on electric. It is an extreme case (the worst I've seen anyhow), but it shows the potential hazard one could encounter. When I arrived at this job site, the sheet metal around the boiler was glowing red hot!
Like Chris said, the recall includes a thermal cut-off (see the last picture). This would have prevented the overheating and potential fire hazard as seen it the 1st 3 pictures.
Note: Thermal cut-off photo courtesy of bigdodgeram. Tim
http://i8.photobucket.com/albums/a23/timsrv/refer2.jpg
http://i8.photobucket.com/albums/a23/timsrv/refer.jpg
http://i8.photobucket.com/albums/a23/timsrv/refer1.jpg
http://i8.photobucket.com/albums/a23/timsrv/Dometic-2.jpg
RE: Dometic Refer Recall - Possible Fire Hazard -Update 2/13/07
http://i8.photobucket.com/albums/a23/timsrv/IMG_6636.jpg
Okay, this thread is hopelessly long, so I figured few would read it all. Kudos to you for your patience;). As for which element to run, I think moving the hot spot away from the place where the boiler cracks, and then evenly distributing the heat to the rest of the pocket would be more important than total watts. I also believe this was Dometic's reasoning in redesigning these elements. If you look at the picture above, you can see the heated portion of the element does not extend all the way to the bottom like it did before.
As for why they didn't replace the elements as part of the recall.......who knows? Perhaps Dometic is more concerned about liability and maybe isn't too terribly concerned about the longevity of the existing refers (just a guess) -OR- Perhaps they figured the stress patterns were already set, and changing the elements now wouldn't matter (just more speculation). Regardless of their reasoning on the older units, I'd be willing to bet they're concerned about the longevity of the new refers they're manufacturing now.
For those of us with the older refers (with original elements), it may be too late to reverse the existing stress patterns, but I'd still feel much better knowing I had the latest element (I'd consider the $40 cheap insurance). BTW, I stock about 10 or more of these elements and try to sell one to almost every customer I run into with a recall refer. Needless to say, I sell a lot of them. Tim
RE: Dometic Refer Recall - Possible Fire Hazard -Update 2/13/07
Keep in mind calculating heating element watts in the manner you did (using resistance only) is not the most accurate method (your estimated watts will always be on the high side). It's totally understandable as I initially made this same mistake myself before giving it some more thought. Anyhow, here is a better and more thorough explanation I posted earlier in this thread. Read on. Tim
Okay, Okay, I'm making some major headway here and had to share it with you all. Please understand It's been a while since my college electrical / electronics training, so this took some thought to get back into the swing of things. I started remembering there are more ways to check watts:h. Although testing resistance is the easiest way, it's not the most accurate way.......especially on something that gets hot. Once you energize an element, the heat changes resistance, therefore changing the calculated watts. Checking in this manner is only going to be approximate and always on the high side (more heat = more resistance).
As I just said, there is more than one way to calculate the watts of a load (3 to be exact). Method 1.= Volts squared divided by Resistance = Watts. Method 2.= Amps squared X Resistance = Watts. Method 3. (and the most accurate in this case) Volts X Amps = Watts
Due to the fluctuation in resistance caused by heat, the best way to determine Watts in an element is to eliminate resistance from the equation.
Okay, now for the good stuff. I energized an element and measured Amps by routing current through my Fluke. When cold the current was slightly higher so I waited for element to heat and stabilize. Once there I measured 2.63 Amps. Using method 3 to calculate (Volts X Amps) this works out to 315 Watts:W.
http://i8.photobucket.com/albums/a23/timsrv/IMG_6634.jpg
http://i8.photobucket.com/albums/a23/timsrv/IMG_6635.jpg
On a side note, remember the old style element I tested? Remember the hot spot at the bottom (right adjacent to the cracked weld)? Well, looks like they did something about that too. Check out the nice even heat of this new element!
http://i8.photobucket.com/albums/a23/timsrv/IMG_6636.jpg
Okay, so I'll have to take back some of my bad thoughts of Dometic (but not all;)). This makes me feel a whole lot better and should go a long way to solving the problem with these refers. I still think they should be replacing elements as part of the recall, but that's another subject. Would also be nice if they put a little more effort into explaining things, but I think we do a pretty good job figuring them out here. Just takes a bit longer to get to the bottom of things. Tim
RE: Dometic Refer Recall - Possible Fire Hazard -Update 2/13/07
Yeah, I keep wondering if they're going to expand the recall to cover a wider range of manufacture dates. I see these things with cracked boilers all the time. I saw 2 of them just last week (RM 2852 & RM 2662) both had the green dripping down around the burner, but both were outside the recall dates (one before and one after). Not sure how they determined the dates of affected units. I still don't believe it was caused by a 29 watt hotter element. Maybe someone at Dometic rolled the dice while choosing the manufacture date cut-offs?:?
RE: Dometic Refer Recall - Possible Fire Hazard -Update 2/13/07
IMO, it's not likely there is even enough hydrogen in the refer to do much more than blow the access door and roof vent off the coach. Even if there was, the area where the gas would collect is relatively small, well ventilated, and fairly well separated from the interior of the coach. An explosion like that would have vented outward toward the exterior anyhow. It's entirely possible a refer explosion could result in a fire, but I seriously doubt the explosion itself would hurt anybody inside the coach. I agree with the other guy that said it was most likely an LP leak. And it would have had to be a MAJOR LP leak to blow the place up. Fire investigators should have been able to determine the source of such an explosion. Tim
