Thank you very much for the information. There were a number of posts a few months ago on this issue and the safety concerns. I've seen a lot of burned-out units in the salvage yards and without going over all the points posted before, this is a major concern to me. We had a fire in fifth wheel in that area.
I ideally wanted to eliminate the propane fridge entirely but I didn't understand that we could have the same problem using just the electric system. Is this because the electric system works the same as propane in that it heats the sodium? If that's true then the issue is still there whether on propane or electricity.
The system with John pointed out replaces the entire sodium condenser system with a 12 volt low power alternative but it's about $1000. It's almost worth just changing the whole fridge out at that price point . A major problem is getting the old fridge out and the new one in... I'm not sure how that would be done except through the front window. If you or others have knowledge on this please share.
Again thank you for the information and clarification.
Robert and Bev Lewis2000 Safari Continental, since 20173126B Cat, 330hpMD3060 Allison
https://safaritoonces.org
On August 5, 2019 5:25:36 PM "W Taylor Hudson fpengr@... [Safarifriends]" wrote:
Robert,You are correct in your assumptions of the Norcold recall module. On early models it wires inline with the coach power supply to the fridge controller, and when tripped, the whole fridge is dead.
The exact concern is not flue temperature, but boiler tube temperature. When the refrigerator is off level (>3 degrees), the gravity flow of the condensed refrigerant to the boiler tube can be used be interrupted. Once all the accumulated liquid refrigerant in the boiler tube has flashed off to gas, there is no medium left in the boiler tube to absorb heat, except to superheat the remaining gas (which has very minimal thermal transfer when compared to a liquid to gas phase change).
There is a snap type thermal switch at the very top on the boiler tube which closes around 115 degrees F to activate the two “pancake” fans atop the condenser coils. This switch and fans are intended to help improve refrigerator performance in hot summer ambient conditions and does not assist in cooling the boiler tube during “dry firing” conditions.
Before installation of the recall thermal limiter, there was nothing to limit heat input to boiler tube during interruption of condensate flow. If the coach/camper remained off level long enough, the “dry” boiler tube could reach 800 degrees F, potentially inducing temperature related stresses. The problem can occur regardless of mode of operation (gas or electric).. Obviously if the boiler tube cracks and leaks while firing in the gas mode, there is a present ignition source to ignite the combustible ammonia gas (ignition point of 1,204 degrees F). Ammonia which has leaked from a cracked boiler tube is said to leave a yellow residue behind. Regardless, due to the sensitive nature of the refrigerant charge in an absorption cooling system, any refrigerant leak will result in appreciable deterioration of system performance.
Those of us that are experimenting with installing fans in our flue spaces and/or at the refrigerator evaporator are attempting to improve cooling performance. Also note that Norcold requires that when flue spaces are more than an inch deeper than the condenser coils (more than an inch of clearance), baffles should be installed in the flue closing this gap (so as to cause most of the convective air flow in the flue to pass over the condensing coils). SMC certainly missed the boat on this as far as my coach is concerned.
When comparing costs of the “Amish heavy walled boiler tube” units, or the 12 compressor based cooling units, remember residential refrigerators can be found that size wise fit the 1200 opening. If you have a 2,000 watt sine wave inverter, you should be good to go except for boon docking, where a cycling generator or a fair amount of solar power is needed. Per the forums, most people that install residential refrigerators never look back. v/r,
Taylor Hudson‘98 Safari Serengeti (4060), CAT 3126acquired 2018
On Mon, Aug 5, 2019 at 4:34 PM robert lewis robert.lewis.tl@... [Safarifriends] wrote:
Jim
The jumper completed the circuit provided by the add on board. I am assuming that the thermocouple on the exhaust stack was monitored by the add on board and when below the setpoint (ie. system off, or in range) the interlock was completed allowing the remaining start sequence or run operation to function. Again my assumption: the add-on board with the micro monitored fail and other fault conditions and provided the above interlock signal. I just bypassed the board with all the checks with the jumper gave a good interlock, therefore not a way to run the fidge, just a troubleshooting operation. John helped me troubleshoot and understand the operation.
Yes I tried the magnet and no luck it would not reset.
That is a clever design you did and I think I understand I used a PID controller similar to yours, for controlling additional cooling fans for my inverter in the power bay. What I don't understand is why the stack would reach excessive temperatures... is this a run away condition and if so what would cause that?
What I would like to do if money where not an object and it seems to be right now... is to replace the whole propane system with the low current 12v compressor alternative John mentioned.
I haven't tried this yet, but was going to look at what the current draw would be on the 120v operation and as an interim solution connect the fridge to the 120v inverter circuit and leave the whole propane system off for the fridge. Do you see any down side to that? Thanks for the suggestions and heads up.
Robert and Bev Lewis
2000 Safari Continental, 2017 - present
3126B Cat, 330hp
MD3060 Allison
https://safaritoonces.org
James Exler jimxexler@... [Safarifriends] wrote on 8/5/2019 12:12 PM:
Robert,
Yes the picture came through; that is how i knew you were talking about the Norcold recall.
If you read your email that I responded to, nowhere did you mention Norcold; no one did or for that matter, where this mystery "red light" is located. When I saw your picture, I focused on that issue and possibly that is not the original posters problem; who knows from the emails.
I see from the picture that you have a jumper instead of the thermocouple. What did that do? Is the red LED on the recall box still on? Have you tried resetting the recall box with a magnet? Is the thermocouple still attached to the burner stack (chimney)?
I removed my recall box and it would fail with no input sitting on my bench when power was applied. I have drawn a schematic of the circuit board and identified the components. Unfortunately, one is a micro processor and I have no way to determine the program it runs so it sits in the "dead letter file".
My solution:
The thermocouple is a K type so I purchased a TC controller from eBay for a bout $10. In heating mode it closes a relay until the set point is reached and the range is up to 500C. I found a patent document for Norcold that talks of a unit similar to the recall box and the limit is set at 430F, about 221C and that is what I set my controller to.
As long as the chimney is below the set point as measured by the TC, the relay stays closed and completes the safety circuit which is the same thing the Norcold box did.
If it tripped by exceeding the set point, my control would turn on again which I did not want so I added a relay with a holding circuit so you can only start the circuit by pushing a button. A dual color LED I added confirms the status, Red for power and ready to run, green for running.
I mounted my system in the panel under the refrigerator in my Journey; a picture of it running is attached. This way I can keep an eye on the temps when we are in the coach.
Jim Exler, Nampa, ID
On 8/5/2019 11:33 AM, Robert Lewis robert.lewis.tl@... [Safarifriends] wrote:
Jim
It just keeps getting better... now the manufacturer's are added to the list of the negligent and incompetent.
I don't understand about the picture, did my picture not come thru?
Yes I would appreciate a fix for this. Thank you.
Robert and Bev Lewis 2000 Safari Continental, since 2017 3126B Cat, 330hp MD3060 Allison
https://safaritoonces.org On August 5, 2019 5:23:15 AM "James Exler jimxexler@... [Safarifriends]" Safarifriends@yahoogroups.com wrote:
Robert,
To put it mildly, "Norcold has had their way with you".
A picture would have saved a lot of time. This is a Norcold recall fix that DOES NOT WORK for very long after it is installed and is non repairable.
Around here the dealers will not touch it because Norcold won't pay much and won't stand behind it.
Now, the good news. I had the same recall done on my Norcold 1210 in my Journey. After it died, I put it back to original and ran one trip that way with no problem. I then devised an alternate control.
Interested?
Jim Exler, Nampa, ID
On 8/4/2019 7:52 PM, Robert Lewis robert.lewis.tl@... [Safarifriends] wrote:
Patrick
My fridge failed in a similar way and it was the factory recall add-on board. John helped me verify the problem by bypassing the board with a jumper on the board input. I cannot run the fridge this way because there is no thermal feed back for the exhaust stack and posses a serious fire risk, but you can verify and see if this is the problem.
I've attached a picture but I'm not sure if it will get through the mail system.
Robert and Bev Lewis 2000 Safari Continental, since 2017 3126B Cat, 330hp MD3060 Allison
https://safaritoonces.org
On August 4, 2019 6:18:47 PM agin.patrick@...[Safarifriends] Safarifriends@yahoogroups.com wrote:
Thanks to all of you Robert, Gary, Marc, Craig and Mel ! I slowly opened the propane valve, I succeeded in opening the stove, I have also hot water now but the check light of the fridge is still there. I opened the outside door of the fridge but don't see anything like a T valve. I tried to join a picture but don't see how with my phone.
Thanks again for your help
Patrick
Sahara 96
Virus-free. www.avg.com '
