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I know there has been quite a bit of discussion on humdity which propted me to purchae an Abbeon. I got one used on ebay. Cosmetically it looks ok but when I have tried calibrating it I get vaying results. I first tried the salt method. 8 hrs in a sealed container. I set it at 75 when I took it out. Then in my shop I checked it with a wet bulb and it was off quite a bit so I set it to the bulb reading. When I took it to other parts of the house and rechecked with the bulb it was off by about 7. So i reset it again and took it back to the shop, still not accurate compared to the bulb. The only thing I can tell is that the adjustment screw seems to turn like the shaft is bent, the needle when adjusted dosen't move it kind of drags and jerks not smooth at all, also there is a lot a dust inside. I wasn't sure if I can gently blow it out or try to vacuum. I don't want to send it to Abbeon because by then it wouldn't be worth what I paid. My only other option is to try to send it back.

Any help would be greatly appreciated

Thanks
Richard

Richard buddy it sounds like there is something wrong with your Abbeon.

My procedure for calibrating mine is to do the calibration in my shop where the RH is in the range that I need to have accurate measurements for. The thing about these hygrometers is that they seem to all need to be calibrated in the range that they will be used. So if you calibrate it at 75% it may be accurate at 75% but way off at 45%.

I use a wet bulb test, do it twice and record the results and then I adjust my Abbeon adjustment screw. Mine turns smoothly and precisely and there is no jerking of the needle.

I think your unit is faulty. When you get it fixed or replaced do the wet bulb in your shop when you know the RH should be about 50ish or less and then calibrate the Abbeon to your wet bulb results. BTW these things drift out of calibration as often as every 3 months. Some units will need frequent calibration and some will be good-to-go for a couple years without calibration. There is no way to know what kind you have without a wet bulb test.

That's kind of what I thought. i plan to send it back. It's funny I have a Radio Shack el cheapo that is dead on with the wet bulb

thanks
Richard

I have both the AB-167 and the C200. The AB-167 needs to be calibrated annually. I also have a wet/dry bulb sling psychrometer, but I found that I needed to take several readings to get a reasonably accurate measurement. The C200 is the best tool I've bought. It's really accurate and I keep it in the case and just check things at the beginning of each season, i.e., when I turn on the heat, and in the spring when the humidity returns. I use the C200 to calibrate the AB-167.

I found out the hard way that those cheap electronic hygrometers aren't worth the money you pay for them. I've had several from Radio Shack and other places and they all failed. It may be an expensive tool, but it is as accurate a hygrometer as you can buy. The specs don't improve with the more expensive models, just the list of features. It gives me something that I didn't have with other hygrometers -- peace of mind.

I have been using the Caliber III for the past few years based on impressive reviews. Apparently, they do a very good job calibrating these at the factory.

In a recent thread on hygrometers, the question was raised as to its accuracy. On the advice of Randy Muthrs, I tested the accuracy using a saturated solution of Potassium Carbonate (you can by online from scientific supply stores). The reason you use Potassium Carbonate is that it will provide a RH of 43.2 near room temperature.

I let everything equilibrate for about 10 hours and then checked the hygrometers -- all this was taking place in a large ziploc bag. Both Caliber III's read 43. That's good enough for me My advice is to just buy a Caliber III (I have had really good luck with them) and verify the reading with Potassium Carbonate annually. If it is off a couple degrees, just make a notation on the device. I have two of these in my wood / guitar room and just replace them every couple years or so. Or if you have the extra cash, buy one of the nicer hygrometers but still calibrate with potassium carbonate - that way there is no confusion.

Simon, I thought the recent discussion was interesting, too, so I decided to try the wet bulb test and found out that my Caliber III was accurate.

You are a lucky man. Mine is off by at least 10 points.

_________________
Waddy

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