Dear WeatherCat station hardware
FYI types,
As promised, here is
da' blow by blow of how I replaced the PC case fan in my modified temperature/humidity enclosure described earlier in this thread. As reported earlier, I purchased this fan on eBay:
https://www.ebay.com/itm/172120113322Sadly I must report that the vendor changed shipping companies with my order and it took another 4 days over what they promised. Nonetheless the product was indeed a 3" (80 mm) fan that would mount on the same plate that I had
"fabbed" when installing the first fan.
The first challenge was to figure out how to power the fan. The previous fan could be powered by providing +12 volts to the yellow wire and connecting the ground to the black wire coming from the fan. The new fan stubbornly didn't work this way. By accident I discovered something shocking! Connecting the +12 volts to the red wire and the ground to black worked perfectly! Of course that is
how it should have been all along - which is why of course I didn't expect it!
Once the matter of actually getting the fan spinning had been solved, it was time to connect the wiring. My understanding is that crimping is preferable to soldering in exposed outdoor environments, but I don't have crimping tools for wires this small. So I removed the solder from the connector and then soldered the new fan leads to the old connector wires:
The previous fan leads had been protected with electrical tape. That tape had started to pull away from the wires, so that didn't seem like the best solution. Since I have purchased a heat gun and heat-shrink tubing, I went that route. Here is the two leads protected in heat-shrink tubing:
As you can see, this is a much tighter and resistant seal. For extra protection, I shrunk a second piece of tubing over the entire wire assembly:
Now all that remained was to clean the radiation shield and install the fan. For reasons I don't understand, the enclosure was more dirty than in previous years. Here is the photo of the old fan and mounting assembly at 1 year:
Here is that same mounting assembly before cleaning:
Every component needed some cleaning and while Simple Green degreaser did a good job of releasing the dust and grime, I'm still puzzled about what caused so much more debris to end up in the radiation shield this past year.
Once everything was cleaned up, I could install the fan using the same fasteners that held the previous fan:
Unfortunately, as you can see it was late in the day at this point and daylight was starting to fade. I took this picture of the fan spinning:
It is difficult to see because the flash stopped the motion and there was very little background light to capture the motion during the exposure. Finally, I took this video with my iPhone so that you can hear the fan spinning.
It is mostly quiet, you need to turn off other sounds to hear it, but it will give you some idea of what the fan sounds like. It is much louder than the old fan and would probably be annoying in a computer. However, for this application it is actually desirable. So long as there isn't any other background noises, the fan can be easily heard and that will serve to confirm that it continues to work properly.
The mean life of this fan is something on the order of 7 years, so I'm hoping I won't have to do this again for a good long time!
Cheers, Edouard