Why is my moisture reading temperature dependent?

[kelLOGg]

I am drying maple in my DH kiln and measuring the MC with a Protimeter pin-type meter inserted 1/4 of the way into a test board with the wires from the probe passing thru the kiln wall to the meter. The MC reading got to about 10% and stayed there for days. The temperature in the kiln was about 90°F. I turned the DH unit off and waited several days until the temp fell to about 65°F and the MC read 6.5%. Turned the DH unit on again and with the temp at 90°F the MC was again 10%.. etc..etc... This has been a problem for years but it seems to be getting worse or I am getting more frustrated with it.

The moisture meter has a temperature compensation feature but apparently has never worked. Anyone else observed this problem? Should the probe and meter be at the same temperature? If so, this method is toast.

[firefighter ontheside]

My delmhorst has a setting for temperature so that it can correct for the temperature.  I would think that yours either has the same feature, or a correction chart based on temperature.

[GeneWengert-WoodDoc]

Rule of thumb for these pin meters that measure resistance and then convert that resistance reading to MC, is that they are accurate at 70 F.  Add 1% MC to the reading for every 20 F cooler, and subtract 1 for 20F warmer.

[kelLOGg]

Thanks, Gene.
I assume that is the temperature of the probe inside the kiln.

[GeneWengert-WoodDoc]

Yes, it is the temperature of the wood around the probe.  It takes a long time for wood to cool, so oftentimes the kiln temperature is valid for several hours after the wood leaves the kiln.