Just completed chamber with woodmizer dh4000 questions!

[canadianwoodworks]

Hello everyone, first post!

I built a chamber 14' wide, 6' tall and 10' deep, I have 8/4 walnut thats air dried 12months and some 8 months and some 6 months.

I loaded the chamber basically to the max, 2 piles deep 5' tall just enough room for the fans and then the baffle.

My question is this, the lumber is at 18% - 25% from what I've read I can pull moisture out as fast as I can at this point. So should I set the controller to rh 0% and 115-120 degrees or do I set it to 30% rh.

I've have this load in for 1 week, the RH of the room is below what the controller can read. Lumber moisture 8% - 12%. If I set the controller to 0% it still makes water but I have to trick the RH sensor by putting it outside.

After I just said all that, is it just that my wood is dry now? If that's the answer, I can accept that!

Thanks for taking your time, i'm mostly a wood worker, but recently aquired a 1992 LT-40HD and the kiln.

[GeneWengert-WoodDoc]

Certainly lumber at 18% MC is safe, but 8/4 walnut at 25% MC is still at risk.  So, stay at 30% RH.  Actually I would like to stay at 45% RH to protect the wetter lumber.

At the age of your equipments, it is likely that the RH sensor is not real accurate.  Your can buy a digital portable sensor for around $30 that will confirm the RH.

The target for most 8/4 walnut would be 6.0 to 8.0% MC.  because of the long air drying, you could have insects, so it would be a good idea to heat with an auxiliary heater to let the lumber reach 130 F.

[canadianwoodworks]

Thanks for the information Gene.

The kiln is actually brand new, the guy had it on a skid still wrapped in plastic, it is pretty new 2013 maybe a 2012. So I think the sensor is fine?

So stay 30% / 45% until under 20% then change the unit to just run all the time which would be 0%

[GeneWengert-WoodDoc]

At 0% and running all the time, when the moisture is low so drying is slow, the cold coils may become so cold that they freeze up.  There may be a sensor on the coils that automatically shuts off the unit when this happens; if not, you need to watch it.

[canadianwoodworks]

I just want to make sure I'm finishing off the lumber correctly. How long should the  8/4 Walnut take to go from 20% down to 8%?

[GeneWengert-WoodDoc]

Drying time depends on humidity and temperature in this case.  At 30% RH, and 115 F, maybe two to three more weeks for all the 8/4 walnut pieces to reach 8% MC shell and core.  Drying time is based on the wettest and not the driest.  Further, although 0% RH can be used, that will over dry some pieces, so you need to use 25% RH to 30% RH.

[canadianwoodworks]

So I guess I'm back to the question why in my RH so low in the chamber? It does not even read, it says 000. If I blow on the sensor it reads 50rh + if I put it outside also get readings from 30-50rh. Currently winter here in southern Ontario.

When I put the batch in I was reading 70rh at 115 degrees

Currently I'm reading 8%-12% on the slabs in here, should I mention it's all live edge slab sawn. I turned off the compressor and left the heat at 115 degrees, my RH sensor reads 000.

The kiln is a woodmizer dh4000 with is a nyle l200 but different controller, it all seems very good quality. I did check through all programming, all settings seem to be where they should be.

[GeneWengert-WoodDoc]

First step is to spend $30 and get a digital readout humidity device.  Note that this cost is very small even with overnight shipping, compared to the value of the lumber.

It is possible that the humidity sensor you have is defective or is programmed to not read under 30% RH.  It seems clear that something is wrong in this area.  So, go to Amazon and search for "relative humidity" and look for a device costing $30.  Or more.  You will see several different items that fit this.  One possible item is
www.amazon.com/Extech-445703-Big-Digit-Hygro-Thermometer/dp/B00069ECFY/ref=sr_1_4?ie=UTF8&qid=1425394483&sr=8-4&keywords=relative+humidity+meter

[canadianwoodworks]

Okay will for sure do that, I do have a cheap gray min/max in there which reads around 15%, I actually assumed my cheap one was the problem. I should be more more open minded perhaps.

[canadianwoodworks]

Okay I got a RH / Temp min/max sensor, It reads 24% RH while my Woodmizer display screen says 12%

I assumed it was the cheap meter that was off, but perhaps its the sensor on my kiln unit or the programming, which I have checked through. But should check again.

[canadianwoodworks]

Figured out pictures!