calibrating humidity devices

[merrydancer]

I just bought two digital temp/humidity devices from walmart.

I did the salt calibration last night for about 14 hrs... that showed they were low by 7%

I just put them side by side with my wet bulb and that showed they were only 2% off,

...any ideas ?????

I thought salt was fool proof/accurate..
I thought wet bulb was fool proof/accurate

Thank you

 

[gabrielle1976]

I am new to all this but I think I would split the diffrence and go that all of them were off by 5%. Nice even number . But I am shure some expert will know something . Good luck

 

[merrydancer]

Yeah.... that is what I am thinking...lol

I am trying to keep my humidity between 40 - 45.... pretty tuff when there is so much difference in reading...

 

[merrydancer]

Hey Gabrielle

We are almost neighbors.
I live in Vancouver, WA

your avitar is a darling pic.

 

[gabrielle1976]

Thank you .
Yeah Im only about 80 or so miles east of you I think

 

[greathorse]

Is the thermometer on the wet bulb dead on? I had the same thing then calibrated my wet bulb thermometer and boom there it was, the therm was off a bit.. My wet bulb thermometer did not read in fractions of degrees either so there could be a point or two there.

I too would be curious to know which is the most accurate. My question via the wet bulb reading is as follows. The hole for the wet bulb therm and the dry bulb there were both on the top with the water pan. That therm read about two degrees higher than the one with the eggs. I used the higher reading for dry bulb wondered if that was correct. Those two thermometers were right next to each other so assumed would use those.

Good question.

 

[merrydancer]

Great Horse - how do you calibrate a wet bulb set up?

Mine is mercury which is supposed to be more accurate than "spirit filled". When I take the "sock" or "wick" off the wet bulb, the one I use for the wet bulb and the one I use for the dry read the same.

I don't know how I would know if them were off.

I have noticed also that I get a slight differernt temp reading depending on where I put the thermometer so I try to get readings as close to the eggs as possible.

I was on line trying to find a very accurate digital thermometer... I did.... it ONLY cost $417 ...

Thought I might order a half dozen or so... NOT

so the quest for stable temp and humidity goes on...

 

[greathorse]

In that case I would assume they are accurate. Or I would by a gross of the 417 dollar ones LOL. It seems to me your devices are close enough for our work.

good luck

edited to say

Sorry you asked about calibrating the wet bulb. I calibrated my thermometer it was one of those ones that you turn the nut to a known temp It was a couple degrees off. They are not known to be the most accurate but I think good enough for the RH work. I dont know that a couple of points this way or that makes or breaks a hatch.

 

[merrydancer]

You have one you can adjust???
I think I would like that!!
The best I can do with my other digitals is say "ok that one reads .5 lower than my mercury.... and that one is .5 higher, except today it is right on..

Adjustment screws seems like a nice option... IF I might ask
what brand... where did you get it....cost??

 

[greathorse]

not digital it is like the instant read meat thermometer I think there is a spring this one is from GQF I am sure it came wiht the bator. I bought the bator used and it had these two thermometers. round dial face you know the type. A nut on the bottom grab it with a pliers and adjust to a known temp.