Control Company (Traceable) 4185 Hygrometer

[mlangfield]

Does anybody have the adjustment procedure for the 4185 Hygrometer?( also sold by Fisher Scientific )

[NC-Cals]

Later models of this meter are not field adjustable. If yours has a probe that is a cylindrical probe all the way down they can be adjusted. If it has a ridge near the base of the probe it isn't. I believe to adjust the meter you hold the °C/°F button and Reset button at the same time to get into the adjustment mode. It will prompt you for 33% and 75% RH. If I remember correctly, you press the hold button to store the point. It may go through temperature cal first.  If it does not go into cal mode, it is not adjustable.  Control Co. (now Fisher) does not give out the adjustment procedures because they believe they are the only company who knows how to calibrate.

[mlangfield]

Thank-you