Hi folks, I have a Lawson Encore conveyer dryer. For some reason I am having drastic changes in heat. Temp can change from 320 deg to 380 deg. in just a few moments. I've adjusted belt spped, height of elements, temp settings, changed size if wire to unit, and also changed size of breaker in my electric panel. And still having issues. Any suggestions would be greatly appreciated.
Thanks
Lets start w/ the basics: How are your reading the temp? Using an infrared heat gun? Or off the heat indicator on the control panel?
Also, did you contact Lawson support & discuss this problem w/ them?
Is this a new or used dryer?
The Dryer was a year old in April. I testing the temp. with an Atkins Digital Thermometer. I've spoken to Lawson in St. Louis several times. Still No help. I've changed the belt speed several times. Changed settings of the front and rear gates, Increwsed size of wire to unit to a #6-3 w/ground, changed the circuit breaker in the main electric panel to a 50 amp breaker still having problems. I don't know if any cooling temps have been checked because I don't know how to check that. I have changed the damper settings to the exhaust tho.
We know that circulation of air in the oven could be a problem.
So do you have an open window or open door or fan or air conditionning that change the circulation of air in your oven? and also with your exhaust: you have like a trap to avoid the wind to come back in your oven?
Nope, No fans, open doors, no AC on at the time. Exhaust pipe is like a stove pipe damper. the exhaust is now disconnected from any pipe, but it was only going to attic area above the drop ceilling. Not even outside. I have tried it both ways. Man I'm running out of options, aren't I?
What is the actual length of your oven area? Also, at what point in the oven (half way, 3/4 way, etc) does the shirt hit 320, and then 380? Is it consistent, does each shirt read the same way? Do you have a forced air setting on your dryer, and if so, it it turned on? Are you sure you're getting proper voltage coming into your bldg, and it's not fluctuating?
The dryer is about 7 ft. long Shirts should reach about 250 deg. halfway through. just before they exit the dryer they should be approx. 320 deg. they are in the dryer for about. 45 sec. to 1 min. The dryer has an on/off switch for its jet air, no other setting. The only thing I haven't been able to check is the voltages coming into the building. However I have already spoken to the local electric Co. Our shop is approx 6500 sq. ft. I have had no other problems with lights flickering or getting brighter or other appliances doing the same. etc.
The dryer is about 7 ft. long Shirts should reach about 250 deg. halfway through. just before they exit the dryer they should be approx. 320 deg. they are in the dryer for about. 45 sec. to 1 min. The dryer has an on/off switch for its jet air, no other setting. The only thing I haven't been able to check is the voltages coming into the building. However I have already spoken to the local electric Co. Our shop is approx 6500 sq. ft. I have had no other problems with lights flickering or getting brighter or other appliances doing the same. etc.
If I understand your problem correctly, the shirts come out at the proper temp sometimes, and at a higher temp sometimes, this all occurring during the same run? Is this dryer new, or purchased used? Have you had this problem since you had the dryer, or how long ago did it begin?
One problem could be something is causing your heat panels to cycle incorrectly. They don't stay on all the time, they cycle on & off depending on the inside temp of your oven, so possibility the temp sensor, or the device that actually cycles the voltage to the heat panels could be suspect.
Another thing that would cause this would be air entering the oven from the front & rear opening, like a strong breeze. Our dryer was located in a warehouse w/ roll up doors, and on very windy days we had to keep the doors half way down, to keep the wind from blowing into the oven, and causing the dryer to overheat trying to keep the temp constant.
I testing the temp. with an Atkins Digital Thermometer.
If your not careful, IR thermometers can give erratic readings. The most common issue is heat reflections. Infrared is a form of light and can be reflected, just like any light.
In the most extreme example, i've used IR heaters to cure powder coating on metal surfaces. When the angle of the thermometer to the metal and reflecting back to the IR heater, i could get readings of over 1,000 degrees, but at a slightly different angle, the temperature would read under 350 degree.
Try reading with a low angle.
fred
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A day late, a dollar short, so it goes.
Fred. Do you mean setting the ceramic end of the thermostat at an angle as it goes through the dryer?
Brian. Thanks for the info. However the unit is in a room that is very temperature controlled. Never an issue with drastic temp changes in the building.
Fred. Do you mean setting the ceramic end of the thermostat at an angle as it goes through the dryer?
Brian. Thanks for the info. However the unit is in a room that is very temperature controlled. Never an issue with drastic temp changes in the building.
What i'm saying is that infrared thermometers are subject to reflection.
If you take a mirror and an infrared to the stove. Aim the thermometer such that the the thermometer uses the mirror to reflect an image of a fire. The thermometer will measure the heat of the fire and not the temperature of the mirror.
The angle of the IR thermometer to what is being measured must not allow a reflection of IR light. Imagine the heater being white light and the plastisol ink being a mirror. If the thermometer were to look into a mirror, would it see the heat elements? If your not sure, when the dryer is cool, place a mirror where the shirt is and look at it at the same angle as the IR thermometer. Can you see the heating element???
fred
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A day late, a dollar short, so it goes.
I have a encore, and I know that the elements cycle on and off.
Meaning they don't increase in intensity to go hotter. They're just on longer.
Just like if you turn down the oven. It doesn't decrease the intensity of the IR element, it just slows down the cycle of how often it turns on.
Stupid I know.
All I do is make sure my gates are low, and that the curing temp is FOR SURE being reached.
Once my dryer heats up it never falters in temperature.... though. There may be an issue with elements.
Oh and I wait like a good half hour for it to warm up. Before I throw anything down it.
Conveyer Dryer Issues. Temp not consistant 
