After several nights of working, the sensor had a fairly lengthy period of no readings of several hours on the 18th and 19th of July. So it was clear that it did not suddenly fix itself. The new sensor arrived on July 19th, and I was able to install it that afternoon.
So far, so good. Hopefully the problem is resolved and I can get another 15 years out of this one!
So of course the next day after ordering the new sensor, it has worked through the night for 5 days. Not that it would have changed my mind, though I might have held off a few more days. It did drop out for somewhat shorter periods for a couple of days, but now has had a streak of solid readings. It might help that the nights are short, as seems voltage related, but other sensors are OK.
I still feel it is intermittent, and probably on the way to a complete failure. The new sensor just shipped today from California, so it won't be here until next week. It will give a few more days of readings so it will be at least interesting to watch.
The first night after complete disassembly and cleaning of the ISS, the temperature and humidity worked through the night. Still, I wasn't too hopeful the problem was resolved.
I had done some research and found this website: https://www.manula.com/manuals/pws/davis-kb/1/en/topic/general-please-read
This is not a Davis site, but I believe a UK reseller of Davis products. But they have supplied a good amount of information, better in many ways than Davis.
They indicate that a temperature/Humidity Sensor has an average life of about 5 years, less if near the ocean. They also say with maintenance, a Davis weather station can expect to last about 10 years with some maintenance.
Interesting that other than replacing the super capacitor once for a failure, my other failure was the console, always indoors and out of the weather.
Since my anemometer seems to be performing better with some lubrication, I decided to order a new temperature/humidity sensor. I'm sure I will also need a ISS Cover/Solar cell in the near future. Hopefully no other failures for a few years.
After another night of Temp/humidity not reporting, I completely disassembled the ISS and looked it over. I did not see anything that looked wrong, but I cleaned it up. I didn't see anything with the temp/humidity sensor obvious, but I also cleaned the cover and filter screen.
While I was at it, I lubricated the anemometer and wind vane. The wind vain was definitely not turning easily. The anemometer wasn't bad. Though it certainly seemed like under 5 mph it was not spinning the last couple of years.
Since the rain gauge and wind speed/direction seem to be working, things are pointing to the temp/humidity sensor. It is as if it works, but when the voltage drops below some level where it should work, it doesn't work.
I am still struggling with whether to spend $60 on a new sensor. I would if I knew the station would work for several more years, but the anemometer is marginal, and the solar cell / ISS cover looks like it has been out in the weather for 15 years.
The Ambient WS-2902 I have been looking at requires some magic to work with Weewx. Not sure I want to attempt a major new project.
As much as prices for the Davis weather stations has increased the last 15 years, and the trouble I have had with my Vantage Pro 2, buying a Vantage Vue ISS would be plug and play with my current setup.
A couple of days after replacing the "Super Capacitor", the temperature and humidity readings are still dropping out intermittently. Mostly at night, but this morning they stopped for an hour or two after sunrise, though I think it was mostly overcast.
So I wondered if the ISS battery was really OK. Weewx reports "signal quality" of the ISS and actually graphs it, and I wasn't seeing any issues. It also reports a "Battery Status" in real time (at the 2.5 sec update rate, though web page only refreshed every 5 minutes. It normally reports just as "OK". I assume if there is an issue, it would report "Not OK" or something similar.
Then today I spent some time trying to figure how to know if the Battery Status ever was not OK, like in the middle of the night. I didn't think so, but wanted to know. I search through some logs, but didn't see any battery issues. Then I did some searching in the Weewx Google Groups pages, and eventually saw that one could make Weewx create an alarm send an email if battery was ever low, or not OK.
That was not quite so easy. It took me several hours to get it working, but I believe it will now send me an email if the ISS battery level drops below OK.
One other bit of information that really should answer the question, is that it appears wind speed and direction is still being reported. A least it was yesterday. Today shows no wind speed, but maybe it is just calm, or very low. I don't think the anemometer works great below 5 mph.
Then tonight, just after dark temp and humidity have stopped reporting. It is looking like maybe it is just a temp/humidity sensor issue. Looking on line, I see some people say they have to replace them every 3 or 4 years. I'm at 15, so maybe I'm lucky?
The Vantage Pro 2 is supposed to be one of the best personal weather stations. I have had quite a few issues with mine, and it looks like I will need to spend some more to keep it running. The Temp/Humidity sensor is $60. Parts to replace anemometer bearings are not available for my vintage unit, so a whole new one is $184 as of today. A complete weather station from Ambient that has similar features is less than $200. The vantage Pro 2 updates readings more often, and it has a better wireless transmitter. But it is not a bulletproof station. It needs regular upkeep and parts will fail. Another option is to buy a slightly lower cost Vantage Vue ISS only. My console will work with it. It's around $300.
A different station will mean doing some updating to make it work with Weewx. Maybe I could sell the Vantage Pro 2 console and logger/pc interface.
Maybe I'll just buy the sensor and hope everything else lasts a few more years.
