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Drying Whiteoak help

Started by Kraynes, December 12, 2024, 06:32:41 PM

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Kraynes

I have a Nyle L200 in a 20' double insulated shipping container, system works flawless on poplar, pine etc. recently loaded 1k bdft of white oak that has air dried to average 26% moisture. 
DB setting on 100 and WB on 97. Load has been in for 3 days and the WB will not go over 93, no water at all has been withdrawn from the unit. Yesterday I raised the DB to 105 and lowered WB to 94, this kicked the compressor on after a while and started pulling moisture, left as is overnight and got 2 quarts of water. 
This morning before work I put the settings back to DB 100 and WB 97.
12 hours later no water has been removed and the WB is down to 87. 
4 circulating fans, good flow through the stack. No leaks in the chamber. I do not have humidification in the unit. 
Temps in my area are 30's in the day 20's at night. Humidity today was 41%

Why can't I get this load to start pulling water? I know white oak is slow, but 3 days and no water is too slow. 
Any suggestions? 

YellowHammer

You've only got a 1,000 bdft of very slow to release moisture wood species in the kiln.  The numbers say the wood will not put out much moisture because you are running at a pretty low DB temperature.  However, since the WB is going down, it indicates your WB wick is wet as it is supposed to be, and so is cooling in the airflow, and it also indicates that the air is drying, so moist air is leaving the chamber....somehow.  

I believe you when when you say the kiln is not leaking, as it is a shipping container, but it does seem you are loosing the little moist air is coming from the wood, and I would assume the only places would be your electrical pass throughs, or more likely, your louvers in your fans and vents.  Especially if you put them where they open toward the outside on the pressure side of the fan deck.  The non powered passive louver should open to the inside on the pressure side of the deck, and the pressure from the fans should force the louvers closed against their stops.  Bottom line, if the compressor isn't running, and the WB is dropping, air is leaving or condensing out of the air.  Are you seeing any wet spots from condensation?  

Even if they are correct, they leak around the edges of the louvers, and I sometimes seal the passive vent totally with a big patch of duct tape in the winter.

Have you taken any moisture readings?  That is pretty critical when drying white oak, it is pretty twitchy.   
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Kraynes

Appreciate the help, the louvers on the intake side do open toward the inside of the chamber, I used a small thermal camera this morning looking for heat/air loss. You are correct, around the electrical entrance there is evidence of heat escape as well as around the bottom seal of one door. I'm sure if heat leaves, moisture will too. 
Overnight the moisture dropped by .75% and I would assume it's leaving around the "heat leaks". 
When I get home this evening I'm going to investigate the inside and looks for condensation. 

K-Guy

Look at your schedule for white oak, you should have your dry bulb much higher by now. More heat helps get the water out.
Nyle Service Dept.
A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.
- D. Adams

scsmith42

Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

Kraynes

I will check the schedule. Poor memory but I think for 25% it showed DB 100 WB 98 but I may be completely wrong. 
Whiteoak is 4/4 thick. 

K-Guy

For white oak at 25% core moisture content you should be at 120°F on the dry bulb.
Nyle Service Dept.
A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.
- D. Adams

Kraynes

I'll raise the Temp this evening. Appreciate all the help. 

scsmith42

If it's at 25% in the core, expect another 10 days, give or take. Typically I'll start sterilizing WO at around 9% in the core.

How are you measuring MC%?
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

Kraynes

I use the probes that come with the Nyle L200.  
In addition I use a Lignomat-k pin meter

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