Davis Temp/Hum Sensor Faulty

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jamie
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Davis Temp/Hum Sensor Faulty

Unread post by jamie »

hamiltonweather.co.nz is back online.

On another note, does it look like my humidity sensor has crapped out? I have a very very low humidity. Very odd considering this is a sensor that is only a couple years old. What are others thoughts?
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Re: General June Weather

Unread post by David »

jamie wrote:hamiltonweather.co.nz is back online.

On another note, does it look like my humidity sensor has crapped out? I have a very very low humidity. Very odd considering this is a sensor that is only a couple years old. What are others thoughts?
Definitely reading too low. Maybe you should consider getting a new one - even if it comes right again in a day or two it might become a recurring problem (like what happened with my anemometer).
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Re: General June Weather

Unread post by Gary McConnochie »

I know this is not on topic but you guys seem to be having a lot of problems with your weather stations. Is this common with Davis?
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Re: Davis Temp/Hum Sensor Faulty

Unread post by melja »

Yeah I have both a cheap one and a good one and the cheap one has been up for 6 years with out fault and the other I don't use now as its giving bad readings.
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Re: General June Weather

Unread post by David »

Gary McConnochie wrote:I know this is not on topic but you guys seem to be having a lot of problems with your weather stations. Is this common with Davis?
Generally no, but there will always be the odd faulty sensor out there and ones which fail prematurely for whatever reason. Even though I've had to calibrate my rain gauge, replace my temp/humidity board and the anemometer I still don't regret getting a Davis.

There is usually a high quality of components, a proper radiation shield, the ability to separate sensors from each other and the ability to watch weather data changing real time. Would happily buy another Davis in the future :)
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Tornado Tim
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Re: General June Weather

Unread post by Tornado Tim »

Gary McConnochie wrote:I know this is not on topic but you guys seem to be having a lot of problems with your weather stations. Is this common with Davis?
Its ontopic now :)

No it is isn't common with Davis Weather Stations.
But Stations that were made in 2006, which I think is when Willo bought the station had a tendency to leak fluid from the super cap, which is the most common issue with Davis Stations.
However with the new stations they have glued the supercap to the PCB to stop it from malfunctioning. This problem is less likely to occur with new stations now.

Also Stations made pre 2006(including 2006 to October) had analogue sensors, these sensors were reliable but the replacement for this is no longer an analogue sensor, its a digital to analogue sensor and these are less reliable going by reports.

Temp/Hum sensors made post 2007 are digital and are generally good.(you can't use these on a post 2006 station unfortunately).

It just really depends if you were to get a Davis now you should have any problems for a while.
I have had mine since 2009 and have not had any problems with it (I still haven't swapped out the ISS Battery yet).

Davis NZ I wouldn't recommend to anyone who wants a Davis station, there customer service is appalling and they charge like wounded bulls.
I got most of my Davis gear from the U.S instead, thats they way I would go down if anyone was to buy a Davis Station.

A very good site that I use if I need Davis gear: http://www.archertradingpost.com/atp/
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Tornado Tim
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Re: Davis Temp/Hum Sensor Faulty

Unread post by Tornado Tim »

melja wrote:Yeah I have both a cheap one and a good one and the cheap one has been up for 6 years with out fault and the other I don't use now as its giving bad readings.
Did the cheap one have no FARS? (Fan Aspirated Radiation Shield)?

Also, I forgot to mention. Stations made pre 2006 had the temp/hum sensor facing up. If any moisture condensed inside the radiation shield it could rest directly onto the temp/hum sensor component causing it to fail.
Since 07, Davis has been recommending to Invert the sensor around to stop this from occurring.

Id check this Jamie, I could come over some time to check it out for you if you wish…..
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Re: Davis Temp/Hum Sensor Faulty

Unread post by jamie »

yea im not sure what to think of it as at the moment its actually pretty close to what other hamilton stations are showing.

65% at the airport
69% here
74% matangi

It seems to be all over the place. Like it was miles out earlier today and last night. Now its accurate.

So ill keep watching it tonight. I cant do anything until the weekend anyway.

If i cant solve it quickly i might take you up on your offer Tim.
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Re: Davis Temp/Hum Sensor Faulty

Unread post by jamie »

what is going on here? The humidity is still correct, however the dew point is too low.
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Re: Davis Temp/Hum Sensor Faulty

Unread post by Tornado Tim »

jamie wrote:what is going on here? The humidity is still correct, however the dew point is too low.
Your DP is correct going by the figures: Temp of 8°C and Humidity of 69% = Dp of 3°C.

Your Humidity is low thats the reason, your temperature is correct.
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Re: Davis Temp/Hum Sensor Faulty

Unread post by jamie »

looks like its fixed itself as of a few hours ago :-k
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Re: Davis Temp/Hum Sensor Faulty

Unread post by Tornado Tim »

jamie wrote:looks like its fixed itself as of a few hours ago :-k
Unfortunately it looks like it has broken it self again...... :-(
Humidity at 23% and dp at -15!

The sensor is under a year old eh....? Should be able to get a warranty replacement then.
If not and if you are keen you can try taking out the old sht10 sensor and replace it with the sht15.....
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Davis Temp/Hum Sensor Faulty

Unread post by jamie »

Um I can't remember how old it is. Must be about 2 years to be honest. I remember getting a new one cause it took them ages to get the spacers for the screws as this sensor is bigger than the old one that was in it. I will pull it apart this weeken. Clean it up and see if I can spot something obvious. Otherwise ill order a new one. How much are they?
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Re: Davis Temp/Hum Sensor Faulty

Unread post by David »

Replacement temp/humidity sensor costs $129 in NZ...
http://davisnet.co.nz/6/replacement_par ... idity_rep/
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Re: Davis Temp/Hum Sensor Faulty

Unread post by Tornado Tim »

David wrote:Replacement temp/humidity sensor costs $129 in NZ...
http://davisnet.co.nz/6/replacement_par ... idity_rep/
Wrong one Dave: Jamies/Willos Station is in the 2006 era so it looks like the upgrade board comes with it: $188.60

I wouldnt bother sending it back to Davis, just get a new sensor and install it yourself.
If you need any help installing it give me a call and I can help you out.
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Re: Davis Temp/Hum Sensor Faulty

Unread post by David »

Oops sorry about that, I didn't realise it was that old
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Davis Temp/Hum Sensor Faulty

Unread post by jamie »

Nothing obvious about this.
ImageUploadedByTapatalk1372462729.756148.jpg
Although an old station this one was upside down in there. I guess all I can do is buy the new one. Ill call them on Monday and see if this one is still under warranty.
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Re: Davis Temp/Hum Sensor Faulty

Unread post by David »

Looks identical to the one I took out of my station. The new one I got from Davis NZ is not really that different... biggest difference is that the black stuff sealing the board is clear/transparent on the new one.
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Davis Temp/Hum Sensor Faulty

Unread post by jamie »

So I get the new one then rather than the old one? I know they had to put spacers in the screws to give enough room in there for this sensor when I got it not too long ago.
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Re: Davis Temp/Hum Sensor Faulty

Unread post by David »

jamie wrote:So I get the new one then rather than the old one? I know they had to put spacers in the screws to give enough room in there for this sensor when I got it not too long ago.
I'm not sure, suggest you ask Davis NZ... the guy on the phone was pretty helpful when I called them about 2 months ago.

By the way, are you going to put the faulty unit back into the station for the time being? The temperature sensor was still working happily at least :smile:
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Re: Davis Temp/Hum Sensor Faulty

Unread post by Tornado Tim »

You need to open up the white mesh compartment to expose the sensor, then you can see if its affected or not.
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Davis Temp/Hum Sensor Faulty

Unread post by jamie »

Yes putting it back in was the plan but i had to rush away on an emergency. Will put it back in tomorrow after I pull the cap off.
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Re: Davis Temp/Hum Sensor Faulty

Unread post by ricky »

Pretty sure with that cap it is the 'new' sensor with an SHT11 inside..
The common problem was moisture getting under the potting and causing loss of data from the resultant electrical leakage path. That would normally show up as both temp and humidity dropouts, ie -- on one or both of the displays. Sometimes just occasional false readings as well.
I think this is more likely with 24hr fars as in fog and mist I saw it can pull a lot of condensed moisture into the sensor area!

Temperature is sampled more frequently than humidity, but both use the same data connection so would see problems on both eventually.
There is a procedure for restoring the humidity performance if the sensor is contaminated, involving a period of baking etc.. have a look at the SHT11 datasheet.
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Re: Davis Temp/Hum Sensor Faulty

Unread post by Tornado Tim »

ricky wrote:Pretty sure with that cap it is the 'new' sensor with an SHT11 inside..
All replacing sensors would be digital , it is just the the replacement board needs to be a model which converts the digital signal to analogue.
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Davis Temp/Hum Sensor Faulty

Unread post by jamie »

Yea under the white casing was just one little black plastic square. Didn't take notice of the numbers and letters on it sorry. Couldn't tell anything wrong with it. Ill just order a new one and talk to the about which one i need. They shroud have me on file from when I got that fixed last time.
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