I Think My Moisture Meter Died.

DR Buck · December 29, 2015, 06:37:02 PM

I have a Delmhorst J-2000 that I've used for about 10 years that may have gone belly up on me. Last week it was erratic and the display kept changing and displaying weird numbers while trying to take moisture readings. I took it into the house and opened it up, cleaned the button contact pads, tightened all the screws and did a reset on it. After that it seemed to work OK and I took about 50 readings on a stack I had in the kiln.

I had the meter set for the correct species and the temperature setting to match the kiln temperature (135º) and had a measured average reading of 7.2% MC for the lumber. Then today after shutting down the kiln over the weekend I reset the J-2000 to the current kiln temperature of 60º did some measurements on the same stack of wood, (still in the kiln) and all of my readings were 5 to 6% higher than when the temperature was up at 135º. I've never had this happen before. My measurements have always been almost identical.

Should I be in the market for a new meter?

WDH · December 29, 2015, 09:02:12 PM

Yellowhammer posted that he occasionally sends his J-2000 to Delmhorst to get re-calibratred. I have not had to re-calibrate my J-2000X yet.

YellowHammer · December 29, 2015, 11:46:56 PM

In order to do a field calibration check, press the check key and read key at the same time, and it will shunt through a known internal resistor. The display should then read 12% plus or minus 0.2. I do this pretty routinely just for my confidence.

If it doesn't read correctly then replace the battery and try again. If still not, box it up and ship it back.

Kcwoodbutcher · December 30, 2015, 07:30:31 PM

That's happened to me before. Replaced the battery and all was fine. If it's more than that Delmhorst used to fix them for 99 bucks no matter what was wrong.

DR Buck · December 30, 2015, 08:06:27 PM

Calibration checks good. Battery was only about 1/2 volt low and shouldn't be the problem. I did replace it and I'll wait to see what happens with the next kiln load before I think about sending it in for repair.

I may look around and pick up another one so I have a spare just in case. Having another one will also give me a way to compare if I get erratic reading in the future.

Dan_Shade · December 30, 2015, 08:14:07 PM

That's kinda like wearing 2 watches. Have you done an oven test?

DR Buck · December 30, 2015, 08:16:18 PM

Quote from: Dan_Shade on December 30, 2015, 08:14:07 PM
That's kinda like wearing 2 watches. Have you done an oven test?

Why do I want to put my moisture meter in the oven?

Dan_Shade · December 30, 2015, 08:38:18 PM

It tastes good with gravy.

Oven test = Oven dry a wood sample and weigh before and after to calculate moisture content.

beenthere · December 30, 2015, 09:57:58 PM

Then use the oven test to calibrate and check the moisture meter. Or buy two more moisture meters and pick the best out of the three.. ;D

GeneWengert-WoodDoc · December 30, 2015, 11:00:04 PM

I suspect the meter is fine, but what you are seeing is moisture on the surface of the lumber...a transient effect. That meter is awesome indeed.

I assume you are using the 26E electrode. Double check that the needles have 100% perfect insulation and that you have the small washers on the needles at the nuts.

If using uninsulated needles, then you are seeing surface moisture for sure.

Incidentally, the average MC is when the pins are driven about 1/5 to 1/4 of the lumber's thickness.

WDH · December 31, 2015, 07:13:16 AM

What is the purpose of the small washers? What would be the effect if they were gone?

GeneWengert-WoodDoc · January 01, 2016, 12:50:06 AM

If the knurled metal nuts touched the surface of the wood, they would read the surface MC if the surface was the highest MC. So, the washers act as insulators.