Author Topic: Rx for a Davis temperature humidity probe?  (Read 142 times)

elagache

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Rx for a Davis temperature humidity probe?
« on: September 08, 2019, 10:26:36 PM »
Dear WeatherCat station caregivers,

With the depravity that seems more common these days, the night before the Orinda Classic Car show WeatherCat reported some sort of sensor errors.  In desperation, I replaced the station battery just before heading over to the show but alas the problem wasn't that simple.

I'm desperately trying to catch up on all the stuff I had to put off in order to attend the show yesterday and trying to revive my station in part of the day's efforts.  Further investigation found that only the temperature humidity probe was not working.  This afternoon I took my radiation shield apart to see if I could understand why. It was dusty but not unusually so.  Here is the plate with the fan:



Here is the temperature humidity probe before any cleaning:



Definitely a bit mucked up but it doesn't look like debris would be the problem.  Here is what it looked like after cleaning:



I don't see any external mechanisms for the failure and after cleaning - alas the probe still doesn't work.  I'm going to order a replacement to try to get my station back on line ASAP.  Still, if anybody has some ideas on how to resuscitate this probe, I'll gladly give them a try.

Thanks for your support!  [tup]

Cheers, Edouard  [cheers1]

Weatheraardvark

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Re: Rx for a Davis temperature humidity probe?
« Reply #1 on: September 09, 2019, 04:31:49 AM »
You need to replace it.  the best price is Scaled Instruments.

https://www.scaledinstruments.com/
Davis VP2 Plus; 24h  FARS; Extra Temp Humid sensor (2); Extra Temp Station (2); Soil Moisture/Temp Station;Weatherlink IP;USB; MAC Mojave; Webcam;https://www.weatherlink.com/embeddablePage/show/1c484adbfa914d1aa10a58ad53ccd563/summary

elagache

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Da' plot thickens (Re: Rx for a Davis temperature humidity probe?)
« Reply #2 on: September 09, 2019, 11:26:57 PM »
Dear Weatheraardvark and WeatherCat station caregivers,

You need to replace it.  the best price is Scaled Instruments.

Yes, that was my guess as well and thanks for the pointer to Ryan Wilhour and Scaled Instruments.  However, it is at this point that the plot took a very curious twist.  Having the non-functioning part in hand I used the part number (7346.166) to immediately look it up on the Scaled Instruments website:

https://www.scaledinstruments.com/shop/davis-instruments/parts/vantage-pro2-parts/temperature-and-humidity-sensor-parts/davis-7346-166-pro2-digital-temperature-humidity-sensor/

It is clearly marked as discontinued.  But no worries, as Ryan lists an alternative part (7346.174):

https://www.scaledinstruments.com/shop/davis-instruments/parts/vantage-pro2-parts/temperature-and-humidity-sensor-parts/davis-7346-174-pro2-upgraded-digital-temperature-humidity-sensor/

Both these sensors are supposed to work in a Davis station manufactured from January 1 2006 and December 31, 2015.  There is just one small problem - even this alternative part is discontinued and out of stock!!  :o

In the meantime, I took a look at Amazon since I am a Prime addict.  Well what to ya' know . . . . . . .

https://www.amazon.com/gp/product/B00PR05X8M/

Not only does Amazon sell the original sensor but they claim they can get more of them.

I tried to figure out what Davis is actually selling on their website, but their new website should be used by the Pentagon to hide information.  I couldn't find anything resembling a replacement temperature humidity sensor for older Davis stations.

Amazon was charging more, but I got 2 day shipping for free so I went with that.  The sensor arrives tomorrow.  I hope to have my station working again before the end of the day.

However, there is something peculiar going on here.  If Ryan Wilhour and Scaled Instruments cannot keep these sensors in stock, those of us with older Davis stations may have a problem getting replacement parts.

Definitely a case of a twisted plot . . . . .  ???

Oh well, . . . .  Edouard 

Weatheraardvark

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Re: Rx for a Davis temperature humidity probe?
« Reply #3 on: September 10, 2019, 01:21:04 AM »
Best of success.  So far my unit is working fine.  I am guessing on a prime weather day, cold , snow , freezing rain, it will crap out.  :)
Davis VP2 Plus; 24h  FARS; Extra Temp Humid sensor (2); Extra Temp Station (2); Soil Moisture/Temp Station;Weatherlink IP;USB; MAC Mojave; Webcam;https://www.weatherlink.com/embeddablePage/show/1c484adbfa914d1aa10a58ad53ccd563/summary

mcrossley

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Re: Rx for a Davis temperature humidity probe?
« Reply #4 on: September 10, 2019, 12:26:15 PM »
The latest VP2 T/H sensor is the one based on the SHT31 sensor - https://www.scaledinstruments.com/shop/davis-instruments/parts/vantage-pro2-parts/temperature-and-humidity-sensor-parts/davis-7346-070-pro2-digital-temperature-humidity-sensor-sensiron-sht31/

There is a slight catch in that if your console is older (like mine, it is) then you have to enter a correction offset in the console...

Quote
This module will also work with Davis Vantage Pro2 units manufactured after January 2006 through manufacturing code AR, however, it will result in a reading which is 0.5 degrees Celsius (0.9 degrees Fahrenheit) too high.  This error can be offset and corrected in the console as a calibration procedure (see page 26 of your console manual for calibration).

The SHT31 sensor is more accurate than the units it replaces, though some people think it has a problem with humidity accuracy over time in high humidity areas.
Mark

elagache

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Thanks for the info. (Re: Rx for a Davis temperature humidity probe?)
« Reply #5 on: September 10, 2019, 11:42:56 PM »
Dear Weatheraardvark, Mark, and WeatherCat station caregivers,

Wouldn't you know it, my temperature humidity sensor is being delivered very late today.  I don't know if I'll manage to install it before I have to cook dinner.

The latest VP2 T/H sensor is the one based on the SHT31 sensor

. . . . .

Quote
This module will also work with Davis Vantage Pro2 units manufactured after January 2006 through manufacturing code AR
. . . . .

Okay, that is interesting.  I was concerned that we might have to purchase a new controller board or something as painful.  Indeed recalibrating is minor matter once you have the sensor installed.  Should I need another sensor, I'll be that much wiser.

Thanks Mark for sharing!  [tup]

Cheers, Edouard  [cheers1]

Blicj11

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Re: Rx for a Davis temperature humidity probe?
« Reply #6 on: September 11, 2019, 11:07:30 PM »
Thanks for the information mates. We'll all be there eventually so this is good to know.
Blick


elagache

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Happy ending! (Re: Davis temperature humidity probe?)
« Reply #7 on: September 12, 2019, 09:32:03 PM »
Dear WeatherCat station caregivers,

Just as we sat down for dinner Tuesday night, the doorbell rang.  Sure enough, Amazon promised to deliver the temperature humidity sensor before 9pm and they delivered.  Alas, that made installation difficult.

However being stubborn, I decided to make a temporary compromise to get the station up and running Tuesday night:



While I'll be the first to admit that this wasn't exactly Kosher and definitely not seismic class-1, there wasn't any significant winds expected and this got my station back on like 18 hours earlier than would have been otherwise possible.

Eventually, I caught up with all the other chores so that I could get back to the station mid-afternoon yesterday.  First, I put the new sensor into the shield plate as before:



I then assembled the lower part of the radiation shield with the PC case fan on top:



Finally, I assembled the rest of the radiation shield and mounted it under our deck:



As soon as the fan was plugged back in it purred happily and the temperature humidity sensor has been working fine ever since.  The only problem is what the temperature sensor is reporting.  Current high is 90.0˚ F (32.2˚ C) and hotter expected tomorrow.  [sweat2]  Our air conditioner will certainly get some business this week!

All's well that end's well!  :)

Cheers, Edouard  [cheers1]

Blicj11

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Re: Rx for a Davis temperature humidity probe?
« Reply #8 on: September 12, 2019, 10:24:46 PM »
Love it. Glad you are back in action. Thanks for the pics.
Blick