Calibrating Humi-Care digital hygrometer

thekenny17

Hi guys, I need some help calibrating a specific model of hygrometer I recently bought from this website. I don't know if it ever came with documentation, but in my excitement to get to the good stuff (the sticks, not the equipment!) I may have thrown it out with the packaging.

Regardless, the thing is sitting in a ziploc bag undergoing the "salt test" for 75% humidity as I type. My question is more in line with this specific model rather than the process. I got the Humi-Care digital hygrometer to replace an older analog one.

I assume to calibrate it I merely have to turn the dial with the drop on it? Part of the problem is I see no change when I turn the dial to know if it's working. Further complicating things is the fact that it is so immediate in its readings it starts dropping continuously as soon as it comes out of the bag, complicating any potential adjustment. Now I'm currently stationed in Afghanistan, so it has a long way to drop! I worry that if I wait until it hits the bottom, somewhere in the 30s I think, and I try to adjust it there that it won't be as accurate as adjusting it closer to the 75% end of the scale.

Does anyone have any tips or experience in calibrating this particular model?

Ken

kuzi16

if you can see through the bag that it is calibrating in then you know how much it is off. my hygrometer is low by 4. i cant calibrate it but since i know its off by that much i will always add that in when i check the humidity. 9 times out of 10 my RH reads 61%rH ... add 4 back in... 65%rH. Perfect. or you can salt test it, remember how far off it is. set it out, let it stop falling, then adjust accordingly.

Mookie91

I've had the same problem. I salt test it to 74%, hit the set button, it cycles through and reads 71%, what gives?

bacon.jay

Yeah, I lost the directions for mine and forgot how to calibrate, and a few weeks ago I needed to. Here's my post about it.

I need Humi-Care digital hygrometer directions...

bacon.jay

Mookie91:

I've had the same problem. I salt test it to 74%, hit the set button, it cycles through and reads 71%, what gives?

You're 100% positive that you're doing the salt test correctly, right? An easier way to calibrate the hygro is to remember how far off it is when you salt-test it. In your case, it's -1%. Then, after you take it out of the bag, leave it out in the open air for a few hours so it can normalize with the ambient room Rh. ONLY after it's stabilized, turn the knob one click and then push the reset button. This will prevent the rapidly changing ambient Rh from screwing with the calibration.