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Nyle L53 Kiln Start Up

Started by maderahardwoods, November 13, 2017, 03:27:39 PM

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maderahardwoods

So I took some readings after work. 

The shorter log is at: 13.3% left side, 16.4% right side
The longer log is at: 17.4% left side, 8.8% right side

WDH, do you think I am drier than I think? Possibly the pinless meter is reading inaccurately?

I am considering purchasing the Delmhorst J2000x kit. 

Thanks,

Marco

YellowHammer

Sounds normal if it was stalled black walnut.  It could also be the meter. 
If the wood is at 17% you should be able to feel it as wet simply by touching it, as well as by weight.  It will also look noticeably darker due to the moisture.  Conversely, when wood is at 8% or lower, it is noticeably dry to the touch.   

I never liked pinless meters for rough sawn lumber.  Delhmorst makes a good unit.

Considering the value of walnut, when in doubt, use the oven dry method. It's dead on, and quite fast measure the weight of a sample board of every day.   Even if you get a meter, always check it by the oven dry method occasionally.

It's hard to devise a strategy unless the moisture content is accuratly known.   

I like 150°F for stalled wood, no extra water on the floor, zero compressor.  Closed vents.  Let it stand at temp for a day or two.  Open the door and see if the wood is "sweating".  When you open the door, you will get hit with a blast of hot humid air, and will see a noticeable moisture sheen on the surface of the boards that flashes off instantly.  The moisture has come from the core of the wood and it will be drier.   

Again, this is the strategy for me on stalled black walnut. 

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

WDH

Make sure that your compressor has not tripped from too high temp, over about 133 degrees.  Take the side panel off and press the little green button to re-set.
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

maderahardwoods

Last night I switched the compressor to "off" and decided to just let the wood sit at 120F overnight to see if the WB would come back up. 

When I get home tonight I will check to make sure the compressor has not tripped and see if the wood is "sweating" at all from being at 120F overnight with no compressor.

If not, I will bump the temp to max (which I think is 140F) and let it sit for a night or two and report back.   

I am considering adding some box fans behind the stack (between L53 and lumber pile) to help pull the air through the stack.  I may just bite the bullet and buy the J2000X, it seems to be held in high regard by Nyle and the FF.  Looks like they even offer some probes to avoid opening the doors to check the moisture content.

Thanks,

Marco

maderahardwoods

The J2000X happened to go on sale this afternoon on testequipmentdepot.com, price dropped from $530 to $387 so I decided to jump on the deal, should have it in about a week or two. 


YellowHammer

As WDH says, the safety trip should be checked.  Or if you can get to it, cycle the compressor on and slide the front filter up and feel the coil, it should be cold.

The L53 should get to 150°F no problem, for sterilization.

Never run the compressor over 120°F.

I used a box fan to augment airflow.  A better alternative is to cut an additional vent opening in the bottom of the unit and fit in a range hood filter.  If you do a search you will find some pics of the mod. It will blow out the dead space in the lower center of the stack.
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

WDH

I run double box fans at the back of the stack between the lumber and the back wall.  I cut the additional intake into the bottom of the unit like YH recommends.  Really helps even out the drying and it also increased the amount of water removal just a bit too.
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

maderahardwoods

So I opened up the side of the dehumidification unit and pressed the reset, didn't feel any type of mechanical "click".  Moisture content is almost exactly the same as the day before.

I switched on the compressor, if I do not pull any water by morning I'll switch the compressor off and let the unit sit at 150F for 24hrs and check for water condensing on the surface. 

I will definitely make that modification to the bottom of the unit once the load is out and can pull the unit out, I will try and add some fans this weekend as well.

How cold should the coil be? I feel like I have touched it in the past and it wasn't all that cold.   

Thanks for the advice gentlemen!

WDH

Do this test.  Make sure that the dry bulb is over 80°.  Set the wet bulb at 75°.  Turn on the unit, compressor, and the heater.  Watch the temps while standeing by the controller.  As soon as the wet bulb temp hits 2° above the wet bulb set point, in this case 77°, begin timing using the stopwatch on your phone or use a watch.  After 5 minutes, you should hear a noticeable "click" which indicates the the compressor has kicked on.  This way, you know that your compressor is up and running.  You have to reach 2° degrees above the wet bulb set-point for the compressor to be activated, then there is a 5 minute delay before the compressor will come on. 

On the panel, if you look at the compressor, it might say "ON" on the panel.  That does not mean that the compressor is actually running.  If means that the conditions in the kiln are such that if you had the switch turned on, then the compressor would kick on in 5 minutes.  It just indicates that the system is ready.  This confused me for a while as I originally thought that "ON" on the display meant that the compressor was actually running.  When I first started running my L53, I did not know about the over-temp shut off on the compressor.  That was not in my manual.  Not understanding that, I ran the compressor while the temps climbed over 130° and it tripped the compressor.  But, I did not know that.  I thought that it was running because the display said "ON".  I could not get any water and I was frustrated.  That is when I took the side panel off to check all the wiring and connections to see if anything was loose and I say that little green button.  Not knowing exactly what I was doing, I mashed the button (pressed the button if you are a Yankee  ;D) and no click, no nothing.  Went back to the panel and turned the unit back on.  Nothing.  This was after 3 or 4 days of frustration trying to figure out what was wrong and after 3 or 4 calls with Nyle tech support.  Sat there by the control panel trying to figure out what to do next (which included sending the unit back to Nyle) and about 5 minutes had gone by and I heard a noticeable "click" from the control panel, and voila, I got water. 

On the re-set button, there is no type of "click".  If you push it all the way in, it will re-set the compressor though.  You need to make sure that your compressor is running. 
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

maderahardwoods

WDH thank you for that reply. 

So last night I decided to crawl into the kiln and see if the coil had any water condensing on it.  I opened the filter and could see a few drops dripping into the catch tray, I touched the coil and it was cool to the touch, but definitely not cold. I may borrow the thermal imaging camera from work and measure some temps in the kiln.

While behind the stack I felt that the airflow was stagnant, I remembered that I had one box fan in my garage and decided to place it between the stack and L53. I think I will pick up two box fans this afternoon and add them to each side of the stack to help the airflow between the slabs. 

Morning Update (Dec 13th, 2017): I swung by before work and the DB was 120 and WB was 85, I took a look in the collection bucket and I had about 1 cup of water collected, not much for 9hrs running.  I am hoping the fans will help with the water pull. 

YellowHammer

Sounds like the system is working properly.  There is a high and low pressure switch in the refrigeration system.  If the compressor is operating properly, the copper line from the compressor going to the bulkhead should be cold, much like an automotive air conditioner line.  There may even be frost on it, but when properly charged, the frost should line stop at the compressor bulkhead.  There should be no frost on the coil unless the system is low of freon.   

It's very useful to listen to the sound of the compressor, and know it, as that will be a very useful diagnostic tool for you in the the future.   

The controller only calls for compressor, but is open loop, so doesn't get feedback as to what is actually happening.  If there is water condensing and dropping into the catch rail, then it is working properly.  With this particular compressor, it is almost impossible to tell of it is fully charged with a set of refrigeration pressure gauges.  In fact, to recharge the system, the charge has to be weighed in to be accurate.

You can very easily bypass the high and low pressure switch by using a small jumper at the terminal block in the DH unit.  I've had to do this several times for trouble shooting purposes.  The electrical schematics should be in your manual. 


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

maderahardwoods

Thank you Yellowhammer.

With MC under 20% for 700-900 bd ft, how much water is typically collected in a 24hr cycle? I understand that the MC of the timber is the ultimate indicator of a healthy kiln, but I feel that the water collection bucket is a sanity check. 

I felt the surface of the boards and they definitely felt dry (and obviously warm).  It did not have that cool feeling a freshly cut slab or even an air drying slab has from the internal moisture. 

WDH

With a 35° wet bulb depression, you have very low humidity in the kiln.  With only that small amount of water, you have to be close. 
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

maderahardwoods

Gents, I noticed when the auxiliary fans are switched off that the WB temperature rises higher then when they are on. I forgot to switch the fans on last night, when I checked the kiln early this morning the WB had rises to 89, usually been sitting at 85ish. I may try power off the the auxiliary upper fans and just run a bank of three fans between the stack and L53 unit. Bumping the WB just a few degrees increased the humidity to 31% from 26%....

I should have the J2000 sometime next week. 

-Marco

maderahardwoods

UPDATE:

So after 24hrs with three box fans running behind stack and two auxiliary fans running no change in water removal rate. So I switched off the compressor, sealed the vents with hard insulation panels, and set the kiln to 150F.  I will let it sit till Sunday evening and check for moisture build up on the surface of the slabs.  Wish me luck.


YellowHammer

Kind of shooting in the dark until you know your moisture content. Sweating the wood does several beneficial things:

Indicates there is moisture differential in the core, and has moved some of it to the shell.

It helps equalize the moisture levels in the boards somewhat by migrating core moisture to the shell and then the surface.

It also will also typically drop the moisture content of the wood by about a percent in a regime where a percent or two is critical.  If you dry to 7%, then sterilize, you will end up at 6% when the load cools, which is the limit where boards start to move around due to overdrying.  Flat boards will start to twist, bow and cup. 

It will obviously sterilize the wood. 

With walnut, it's not uncommon for me to stall at about 10% with wet spots at 12%.  So I jack the temps to 150°F, hold for 24 hours, then the wood will drop a percent or two to 8% to 9%, as the system cools down, and then run the compressor to get to 8% to 7% or so when it hits 120°F if I need that last percent or two.  Don't go to 6%. 
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

maderahardwoods

Yellowhammer thank you for the excellent advice/information. I am thinking the MC reading is close to what the meter is reading, because the meter does read consistently when placed in the same sports and has been showing a trend.  I think it had a lot of trouble when MC was above 30%, it will be interesting to compare the readings to the Delmhorst unit. 

I am wondering if the high temp. environment of the kiln affects the pin less meter reading.  I know the Delmhorst has temperature correction

Im hoping the moisture content will even out along the length of the boards.  I will definitely pop in through out the heating cycle and take measurements. 

Once you reach the end of the 150F wood sweating, do you allow the kiln to cool with the high temp vents, or even open the doors? Or do you just kill the power to the heaters and just let it come down nice and slow?


YellowHammer

I don't go in the kiln during the heating cycle, there is a chance to loose heat, and more importantly, loose moisture.  I don't like to loose moisture during the heating cycle, it could be problematic for species that are movement prone. 

Conversely, for some species, opening the door after the 24 hour heating cycle, and venting the heat the moisture, then shutting the door and continuing to heat is a good way to keep dropping moisture, similar to a conventional kiln, without running the compressor.

The cool down process is wood dependent, and I have seen different behaviors using different techniques, on different species, and what my intentions would be with the final product.  Each is also dependent on knowing the moisture content of the wood. 

Specifically, for walnut that I want to dry dead flat, and is high value, once I know the moisture content is about a percent or two above where I want it, I will let the load stay in the kiln, with the temp above 145°F for a couple days, and then let it slowly drop with the vents closed and let it "relax and be happy" on the way down.  I call it the "crock pot" cycle.  Also, for walnut, I like to put several thousand pounds of weight on it when I put it in the kiln.  I use marble scraps that are piled on top of pallets, are very heavy and thin, so don't take upon much room in the kiln.  Typically, depending on your airflow pattern, you will probably see that your top couple layers of wood will have more wave and curves than the rest of the stack.  That's lost money and extra work to fix, and a little weight will keep these top layers flat, like the ones lower down.  Heres some piles of marble as I get them.



For stable white wood, or other types, I'll pull it out fast with minimum cool down.  When you do this, you can hear it moving as it cools down, creaking against the stickers, "talking" as it cools.  Since I have multiple kilns and dry about 20 different species, trying to get a load out even 7-9 days from the DH units, I can observe the behaviors of the different species on a fairly consistent basis. 

The important thing about drying for high quality is to look and observe the patterns and try different things.  Although its easy to ruin a load in a kiln, its also easy to dry wood adequately, but its more difficult to dry high value wood with minimum defects.  That's what makes it interesting.     
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

maderahardwoods

YH thank you again for the excellent information. I plan on making concrete weights in the future, but currently I am using 3" ratchet straps to secure the slabs against the 8" I-beam bunks the lumber sits on. So far it seems to be keeping the slabs flat and prevents them from falling if there was ever an earthquake or other disaster. 

So the kiln hit 140F around Saturday morning, I have been checking on the unit periodically and this morning (Monday, Dec 18th) the DB was 146F and the WB was 110F, so I am maintaining the 35 degree depression.   

I hope to hit 150F by this afternoon, but it is going slow.  I think I will cut power to heaters this afternoon and let it "crock pot" until the kiln reaches 120F, I will then  re-power on the compressor. I had Delmhorst quote me the probes and leads required to monitor the kiln from the outside to prevent unnecessary heat loss from crawling around in the unit. 

WDH

When I am at a 35 degree wet bulb depression, my wood is dry.
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

maderahardwoods

Cut the heat from the L53 and space heater last night (DB 147.3, WB 112.8), removed extra insulation from vents (vents still closed), fans running.

Checked on it early this morning, DB was 133ish and maintaining about a 35F  depression. 

Stuck my hand in through the vent, it did not feel humid in the chamber. 

-Marco


YellowHammer

Ball game. 
When is the meter coming in?
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

maderahardwoods

I was hoping this week, but looking like early next week.  I may just let the kiln cool down to ambient until the meter arrives. 

-Marco

maderahardwoods

Just called Test Equipment Depot, I added 2-day shipping. Hopefully it arrive this Friday. 

maderahardwoods

Just checked on the kiln, the DB is 123F and the WB is at 98F. The wet bulb jumper up 10F! I decided to switch on the compressor. 

I peaked into the chamber and did not see any "sweat" on the boards, but I am hoping the pores of the board opened and will allow the hard water to come out.

I should have the meter Thursday evening, just got the tracking number. 

I will take some MC readings tomorrow with my pinless, can't wait to compare results. 

-Marco


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