dougrainer wrote:
S-J-Chris. Are you an Engineer? Also, when commenting on temps in the USA, use Fahrenheit, not Celsius. 99% of people do not want to figure out C to F. That said, the normal operating range is about 350 to 400 degrees F. The TRIP temp of the Norcold recall box is about 750 degrees. The trip temp of the Norcold and Dometic temp disc is about 800 degrees.
Doug
I do have a background in engineering (computers). Probably not too helpful in figuring out mechanical/chemical systems, but helpful for logically trying to analyze things...
For reference:
180*C = 356*F
190*C = 374*F
200*C - 392*F
220*C = 428*F
It seems to be (based on what I have read online, not based on anything I have measured yet myself) that normal, LEVEL operation boiler temps are usually in the 180*C-190*C range (~350*F-374*F).
I am surprised/stunned (anyone else??) that Norcold and Dometic have a trip point sensor/disk that doesn't do anything until 750-800*F. That is insanely hot given normal temps are in the 350*F-375*F range. I wonder what their rationale is for this, and why they didn't make it something like 500*F or 550*F. Anyone know? Once the boiler temps get all the way up to 750*F-800*F internal water has boiled, rust preventative solution has started to crystalize, system pressure must be through the roof....damage is being done. I guess this is the reason for a DIY thermostat (or Fridge Defend) as these can be programmed to turn off the refrigerator as soon as temps get above say 410*F and before overheating damage is being done. Makes sense to me.
dougrainer wrote:
As to off level. People forget all those times when traveling they stopped for a few hours to sight see or eat and those times start to add up. Rarely when pulling over will you be level for safe operation. Doug
I agree, and disagree. Also, driving up a long steep grade will put the refrigerator at a tilt, sometimes beyond the 3 degrees/6 degrees recommendation threshold from Norcold and Dometic. BUT, it sounds like 3 degrees side to side and 6 degrees front to back (relative to the refrigerator, not the RV) is a pretty significant tilt. I saw someone else calculate that 3 degrees came out to a 5 inch difference over 8 feet. So, if your refrigerator is mounted against a side wall of the RV, and your RV was 30' long, in order for you to be 3 degrees tilted side to side (refrigerator), the front of your RV would need to be about 18.5 inches higher (or lower) than the back of your RV. And front to back (refrigerator) 6 degree tilt you would need to be 10 inches higher on one side of your RV compared to the other. That seems like a pretty significant tilt. In contrast, almost every time I've pulled into a camping spot and I've wanted to level my RV, I have been able to do it with just a few of the yellow leveling legos with maybe a maximum of 3-5 inches of lift needed on a couple of the wheels (meaning that even if I had done nothing the refrigerator would have been "level enough" to work and within the 3 degree / 6 degree requirement.
dougrainer wrote:
Rarely when pulling over will you be level for safe operation. Doug
I disagree. I think a huge percentage of the time when you pull over and park it will be well within the 3 degree / 6 degree spec. Sometimes yes it might be off level more than 3 degrees / 6 degrees, but rarely.
Regardless of all the above, If a thermostat is installed on the boiler such that it shuts the refrigerator down if it gets too far above "normal boiler temps" and it can keep the boiler from going over 220*C (428*F) then it seems like it can do a pretty good job keeping the refrigerator cooling unit from getting damaged due to overheating, which can cause leaks, rupture, cooling unit death, and maybe a fire.
I'm not really overly concerned with this. I think I'm just addicted to tinkering with and adding modifications/upgrades to my RVs (especially safety). This would fall into the safety and preventative maintenance category and seems easy enough to do and cheap enough. I purchased the parts (less than $25). When I install it I will post an update.
-Chris
