I did read this post before making the decision to install the transformer. My line voltage was 120 volts before installing the transformer which (Volts X Amps = Watts) would give me 348 Watts. Now that the voltage applied to the heater is 113volts I have 327 watts. Since the performance of the refrigerator hasn't changed I feel it was worth ten dollars to lower the heat applied to the poorly manufactured cooling unit.
Do you recommend the replacement of the heating element because of the hot spots you found on the older element? Thanks again for the info.
Mark W.
timsrv wrote:
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
timsrv wrote:
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.
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!
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
