adding heater to L53 unit?

[RussMaGuss]

My L53 has been running for like 2 weeks straight now with around 600bdft of white oak. As far as I know it has only reached about 98 degrees in there, though the MC has dropped from about 26% to 18-11% so maybe I am catching it as soon as the compressor is done, though I don't see any water on the ground outside. I have insulated the inside of the 2x4's with fiberglass, and put 2" pink foam insulation over the studs. The ceiling has 4" of pink insulation and the floor has 6" fiberglass. The whole building including the ceiling is tyvek'd. The Doors all have weather stripping on them as well, so it's a pretty tight ship. It was only about 20 degrees when I went out there today. I am considering adding a space heater for additional heat. Would it be a bad idea to run one in there at the beginning cycle to get it to 110/120 degrees and again for bug kill cycle? It took a little over a week to get from 35 to 98 in there and I figure adding a space heater it could probably get there in a matter of hours. My readings before I opened the door to check MC were: dry bulb-98.4 wet bulb-77.1 Heater:ON Vent: OFF Compressor: OFF Humidification: ON. 1 more question I had is: the switch for humidification is turned to off (the other 3 are ON), yet the digital readout says it's on, and I don't even have the sprayer add-on for the unit... Any ideas? Thanks for any input, it's appreciated!

EDIT: At the start of the cycle, I had the dry set to 110 and wet at 98. Now I have dry at 120.

[rjwoelk]

My understanding  is you need to bring your temp up to 80 degrees . Then the kiln unit will start making its own heat.
Others will chime in on this as well. 

[YellowHammer]

The compressor will not kick on until the temperatures are above 80F.  With the L53, the heat strips and compressor will not run at the same time, so if your compressor won't bring the temperature up after it hits 80F, then you will either have to move south, or add additional heat.

Nyle sells a heat unit for the L53 but I believe it only ruins on 220V and you may not have that at your kiln as the L53 only needs 110V.

I add uo to 2,000 watts of heat using 4 halogen 500 watt heat lamps.  They are UL listed, sealed to dust, and available at Lowes, Home Depot or Amazon for $20 each.

I had a bad experience with a space heater in my kiln when the internal fan corroded and died within a few weeks, almost causing a fire.

The display only signals if the controller is calling for humidity, not if it is actually on.  Since you don't have the option, then the unit is operating correctly.

[WDH]

It is important to capture and measure the water exiting the dehumidification unit.  The wet bulb depression and the amount of water removed from the kiln in a 24 hour period tells you what is going on inside the kiln and the state your wood is in even without having to check the moisture content of the wood.  

[YellowHammer]

I agree, the most important accessory you can install on a DH kiln is a 5 gallon bucket.

[RussMaGuss]

So next on the agenda: add halogen lights and put a bucket under the drain hose, got it! Thanks guys! 

Is there a relay inside the controller that might automate the halogen lights? I'm guessing it's going to be more of a balancing act between how many to keep on/off so the exhaust vent isn't constantly running

[YellowHammer]

I generally run 2 lamps, but can do 4 for the initial heat up.  Make sure the lamps are not near a wall or other flammable object, I prefer to put them where the fans blow or wash over them to get heating and mixing.  They get hot, that's the point, so do not put them where they can burn your kiln down.    

The idea is to switch roles and use the L53 heater as the the switchable controlled heat source, and the lamps just keep a steady baseline.  In your case, (and mine) the L53 heater is 1,000 Watts, and won't provide enough heat during cold temps, so 2 of the 500 Watt halogens will match its heat input, and then L53 strips will make up the difference by provided an automated 1Kw of extra heat.  Once the compressor kick in, the halogens or aux heat may not be needed, but if they are, then plug the halogens back in.  Remember that the when the compressor is running, the heat strips on the L53 are disabled, so if the compressor  won't provide enough heat to maintain temps, you will come off your temp set point.  If you need aux heat to maintain temps, the L53 strips won't be energized.  So that's where halogens come into play.       

If you are using the auto vents, then they leak like a sieve, and you are losing a lot of heat through them.  Once the season gets colder, the heat loss will be more than your strips can keep up with.  So duct tape, yes good old duct tape, over the non powered vent from the outside.  Seal it up.  It will reduce heat loss significantly, but will not totally incapacitate the powered vent.  It will simply stall the air, or provide minimal ventilation.  If you can't come up to temp, the powered vents aren't needed anyway.  So first thing I'd try is magical duct tape.  Then 2 halogens, or 4 to boost and 2 halogens to maintain, with the heat strips controlling the final temps.  That should provide a significant improvement.    While you are doing all this juggling, watch the temps, and don't let things overheat or you'll pop your high pressure Freon safety, the mythical "little red button." 

Most times in the winter, I'll boost up with 2 or 4 lamps, and then only run one during the kiln drying cycle if it's cold.   

[WDH]

My L53 chamber is well insulated, so I do not need the halogen lights to maintain heat while running the kiln in normal mode.  In fact, I have to vent and dump heat with the vents as the wood dries to keep the dry bulb below 130 degrees.  The heat from the compressor motor and the auxiliary fans generate heat more than enough to render the unit heater unnecessary except for initial heat up or to sterilize the load once the target M% has been achieved. 

I use the halogen lights (2) to kick start the initial heat up to get the chamber to the dry bulb temp of 80 degrees required for the dehumidification unit to function and to heat up the chamber for the 24 hour sterilization at 150 degrees.  Once the chamber is up to 150 degrees, I do not need the halogen lights to maintain the 150 degrees.  The L53 unit heater will maintain the 150 degree set point.  A well insulated chamber will surely save you money and pay out in lower electrical costs to run the kiln. 

[xlogger]

I built my kiln near my OWB and piped in hot water thru heat exchanger, with Stan's help we rig it up so I can run DH and heat at the same time. I've really need to do a better job on my walk in door and attach some insulation board to it. I struggle to keep temp over 140° when temp gets below freezing at night. 

[RussMaGuss]

So I added 2 halogens and it works great! 1 thing of interest is that the other day when it was like 8 degrees out, it would hit 120, then drop steadily for like 4 minutes down to around 113 degrees and then kick back on. Is that enough time for the compressor to do it's thing? I've got about 600 bdft of 4/4 white oak in there and the boards read between 4.7 and 11% depending on which part in the kiln and what depth setting (1/4" or 3/4") I talked to stan the other day and he said there would be almost no water coming out, which is true, so it seems like all is how it's supposed to be. Before I go to the bug kill stage, what is the high end MC I should be looking for? Would 8% reading at 3/4" depth be acceptable, or should it be lower just in case there are wet spots in some areas? I wish the wagner meters had a 1/2" reading so you could go to the center of a 1" board, but maybe they work by measuring the center even if it goes deeper than halfway

On a side note: I have been trying to understand what exactly the DRI is. The Nyle manual says in an example that a 1.1 DRI *might* be drying at 3% MC per day. Is there a way to do that math without a meter or is it just a shot in the dark? The chart says with 120 and a depression of 32 the EMC is 5.4, RH should be around 30 and the DRI is 2.4. Is there any magic spot on these charts where you know that the load is pretty well done all around? I just don't want to pull it too early and have to re-load

[WDH]

When my dry bulb is over 120 degrees and the depression is in the mid 30's, I don't get very much water anymore and I check with the moisture meter and I am almost always at 8% and done.  However, white oak is the most difficult wood for me to dry.  It can fool you.  I would shut off the compressor, close the vents, run the heat to 150 degrees on the dry bulb and hold for 24 hours.  During this time, open the doors wide open for about 30 seconds twice during the 24 hour sterilization to let out any water vapor.  At the end of the 24 hours of 150 degrees, check your moisture contents.  If at target, you are all sterilized and done.  If not, you can let the kiln cool down below 130 degrees and turn the compressor back on to get out the last bit of remaining moisture in the wood.  Don't run the compressor with the dry bulb over 130 degrees or you will trip the compressor and get to meet the little red "reset" button. 

[YellowHammer]

Halogen lights rock, they are great for this. 

Doing the sterilization "double tap" as WDH describes, is a good way to check the wood and clear out any wet spots, if there are any.  

[RussMaGuss]

Great advice, thanks! yesterday afternoon on the 1/4" setting the meter showed 5% as the highest MC and on the 3/4" setting the highest was 10% so I'm thinking probably 1 more day and then up to 150? Or maybe opening the doors twice at 150 would do the trick. Sounds like worst case would be that I sterilize first and then have to leave it in there another day or so? Very excited to unload my first batch from a non-solar kiln! 

[jwoods86]

@RussMaGuss for the Wagner moisture meters you can use the 3/4" depth setting as it'll work just as well for you. If you have any other questions I know their customer service is great with stuff like that.

[RussMaGuss]

So I guess the load wasn't completely done. I took the baffles off and measured every board I could reach on the face of the stack with my orion 930 meter. 97% were between 4-6% but out of nowhere there's like 3-5 boards that have spots at like 12%. Should I just pull the load and toss these in with the next load of white oak I dry? I turned on fan 2/2 instead of just 1 box fan so hopefully that will help. How long do you guys think it will take those few boards to equilize to the rest in the kiln? 

[GeneWengert-WoodDoc]

It is an excellent building you built, from an insulation viewpoint.  One addition for your cold climate is to,put some insulation on the exhaust fan opening during the winter as you will not need the fan and so this will help even a bit more.

Are you using a pin moisture meter or pinless?  If pin, how deep are the needles?

[RussMaGuss]

Hi Gene, I'm using the pinless dual depth (1/4 and 3/4) Wagner Orion 930. And yeah, I shoved some insulation in the vent holes when I noticed it was really struggling to keep high temps. 

The oddity with the pieces at 12% were at 3/4 deep. At 1/4 they were around 7-ish

[YellowHammer]

Wet spots are a routine occurrence with some species, and first it's important to identify their general location to detect a facility pattern, if there is one.  

Are they near the walls?  In the corners? In the center bottom?  Where?  One of the best mods for an L53 is to cut a hole in the bottom, and open that up.  I had a topic on that years ago.  

When drying wood, the load isn't done until all the wood is dry, if you test a few boards and find a few wet spots, then extrapolate that fraction throughout the load, including boards that are buried in the stack where you can't get to them.  So there is probably still lots of water in the wood to be removed.   

At these low MC's, it will not hurt to raise the temps to 150F and go through a sterilization cycle, which will help drive moisture from the wood.  Then let the kiln come down to 120/125 and hit the compressor again for a few days, and repeat the high temp step again, if necessary. 

I have unloaded a kiln before to remove problem boards, and that works, but in many cases, once I got into the stack, wet spots were problematic throughout and I ended up putting the whole load back in.

I'm always more confident in pin meters on rough sawn wood.  I would pull a board and do a quick oven dry test to make sure the meter is reading correctly.   

[RussMaGuss]

Yeah the main wet spot is more towards the bottom in the middle of the stack. It's perfectly in line with the intake of the unit which is a little funny to me because you'd think it would be getting the most moisture pulled from it, but at the same time I guess you have the most moisture moving across that board that could be reabsorbed. I decided on keeping the load in there as I have a job that is keeping me busy for the next few days, so I may as well just leave it in there for now. Plus we got dumped on with snow over the weekend and I'd need to clear a path to the kiln for my machine, so I gotta have a decent amount of time to work on all of it. Might as well make sure it's all fully cooked. You can't really nuke lumber too much in one of these units, right? (as in, remove too much moisture)

I searched for the l53 modification and will definitely be doing that as it seems like a huge help for loads that are more than a couple feet tall, thanks for the tip! 

[YellowHammer]

Along with the big hole in the bottom, I have additional fans on the fan deck.  It's very important to blow the dead spots out, and get fresh air moving in there.  A wet spot in the bottom center is actually pretty normal for these units, but the mod will help a lot.  

You got to work pretty hard to over dry oak in these kilns.  Much more likely is under drying, especially with a wet board core.    

Plus the fact that white oak is almost as bad to stall as walnut.