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Conveyor dryer problems

26982 Views 36 Replies 10 Participants Last post by  Marcc
I am having issues with my 1 year old electric conveyor dryer. I cannot find a temperature and belt speed that will work consistently. I can get good results for a couple of hours then all of sudden the temp shoots up 20F - 30F and the end result is dye migration with red ink on black 50/50 t's.

This has been happening off and on for MONTHS. The dryer mfg says its user error, and for a while I was going along with them. Now I'm not so sure.

I had a friend stop by today to install an ir probe to monitor the temp at the out end of the dryer. Sure enough after about 2 hours of steady curable temps, the damn thing shot up 20+F degrees. From that point on it was hit or miss. I reduced the ambient temp control down from 360F to 335F and things seemed to work for a while then the temp dropped below the acceptable curable temp. I had to increase the ambient temp back up to about 345F to get back to cure temp.

From the start, I have been using the heat sensitive test strips along with a hand held laser temp gun to gauge my cures. When the strip hits 335F the laser gun is usually between 340F and 350F and I use those numbers for my goal to proper cure. Stretch tests and wash tests confirm that proper cure has been achieved.

I am at my wits end with this dryer. DOZENS of ruined shirts and countless hours of down time and reduced production times are costing me dearly.

Has anyone else ever had a similar problem? I realize the weather conditions can play a role in this, but it doesn't matter if it's winter, spring, summer, or fall....the problem remains the same.
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We had this same issue several times with the older dryer we had before we just decided to get a new one. It was ALWAYS a shorted wire somewhere. Whether it be to one of the elements or a wire to the thermometer ... not the thermometer but it's getting late and I can't think of the word for that part. The part that regulates the temperature of the oven, lol. Every single time we had an issue this was the problem. We would call any ole electrician who would bring their wire tester and test the wires, replace the one that was shorted, and we would get another year or so out of our 200 year old conveyor dryer.
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look at your connections where the dryer is hooked up. Is your dryer the only thing on the circuit?? I would assume it is but you never know. Sounds like your dryer is getting over loaded or underloaded at times. Could be a simple fix, get a volt meter and check it.
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I like the 200 year old comment. I have a Pyramid conveyor dryer made by Phoenix. I have had repairs done on the electronic guts of the machine by a technician who specializes in these types of equipment. I spent $1200 to get it running again. It has done thousands of tshirts since and still works great.
Thank you for the input. I appreciate any and all help with this one.:)

I purchased a volt meter a few months back at the request of the dryer mfg. Main voltage was steady at ~242. This is a single phase dryer converted to three phase.

The temp gauge built-in to the dryer remains constant (+/- 5F degrees) all day long. I guess this tells me the temp in the center of the dryer, where the thermal probe is located, is not being affected

The thermal probe I had installed yesterday at the rear of the dryer backs up the fact that the output temp is increased after a couple of hours of use.

It's just the output end that seems to be getting too hot. As soon as I put my hand near the output to take a reading, I KNOW my temps are going to be 20F - 30F degrees higher than they were previously.

This dryer has 4 heat panels and the front panel indicator lights show them all working together, on and off as needed to maintain the temp.

I am going to have to waste another day today experimenting, testing, checking, and adjusting to see if I can conquer this beast.
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The technician that worked on my three panel conveyor dryer detected the main controller module was defunct so he orders this $250 part from a company back in Atlanta or whereever. However, once the part arrives and the technician installs it, nothing worked properly. After testing it over and over again, the technician believes the problem was the part so he orders another. He installs that and the dryer has worked properly since.
This technician charged me $135 an hour so the repair came to $1200.
My machine is a three phase similar to what you describe.
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The mfg had me replace the temp controller 6 months after the dryer was purchased (new). Things seemed to be ok for a week or two then BAM! ... back to it's old tricks. I lost (melted) a $60 jacket on that one.:mad:

I have been attempting to print a simple red on oxford job this morning and discovered my dryer settings from yersterday were not valid for today. Yesterday the dryer needed a setting 345F for a cure and today it is 360F.

Today I also noticed that the left side of the dryer runs about 15F to 20F degrees hotter than the right side. I guess I can use that to my advantage by using the left side for curing the backs (first print location) and then use the right side for curing the front side (second print location) which will have less moisture content due to the initial pass through the dryer.:D

The dryer has been running now for 2.5 hours, and unlike yesterday, the temp is staying consistant so far. Same weather conditions (hot and humid) both days.:confused:

The mfg of this dryer is trying to get me to buy an $35,000 automatic from them. RIGHT, like that's ever going to happen. I will learn from this experience with them and move on.;)
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Much of the advice you have been given thus far is on target. Checking incoming voltage, etc.

Here are some other things to consider regarding temperature fluctuation in a dryer.

Ambient Air - I know you said the days were roughly the same in temperature and humidity, but sometimes people overlook some flow issues. If you have a fan blowing on either end of the dryer(often to cool the person printing or cool the garments on a dryer with short out-feed) that fan can dramatically change the conditions in the heat tunnel. Did you have a roll up door open one day and not the other? Its those kinds of things that change how the air moves in a shop that can effect dryer performance. Not necessarily on the scale you are describing, but it sounds as if you are needing to check everything you can.

Does this dryer have any kind of booster circuit for temperature that would cause any of the panels to be bypassed from the temp controller? Some dryers have a flash mode that allows the temp controller to be bypassed on the initial heating stage(constantly on to get the garment up to temp faster). These dryers may also have reversible belt direction. If you had a reversed direction with flash on, it would do exactly as you are describing by leaving the last elements on constantly.

If your dryer is getting too hot vs too cold it sounds like the relay for the panels that are furthest away from the probe might be staying on too long. You stated that the probe is indicating the dryer is in range but it is getting too hot near the exit. I don't know what brand you are using, but if possible, you can switch the relays for the panels around to see if you can move the problem. That doesn't cost any parts money up front but will allow you to rule in or out one part of the control circuit. If you do this, make sure your connections are tight. Loose connections will cause you more problems.
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Thanks for the great feedback Tim.:)

As for the ambient air, that seems to carry little or no weight in regards to the problem. I have experienced this problem more than a few times over the past year. In winter the doors are all closed and no fans. In the spring, the door (NOT large overhead type) is open and any breeze that may come in does not blow directly into the dryer. I realize ANY breeze can draw air to/from the dryer, but I still say this is a non-issue in regards to the problem. Yesterday when I experienced the problem, I had all fans off and there was little to no breeze coming in the door at all.

The most trouble comes after a couple of hours of continued use. Most recent issues were with black 50/50's, once with athletic gold ink and this last one one with red ink. I've also had problems with red 50/50's and white ink. I'm sure it's happening with light colored shirts as well, it's just not as noticeable.

I have no idea if this dryer has a booster circuit or not. I do know that it was designed to have a reversable belt but the mfg decided it was not necessary, and without telling me, they delivered it with a one way switch only. (That's another story in itself but we'll not go there right now.)

I like the idea about switching relays. Now all I need to do is figure out what's what under the hood of this Brown UltraSierra 4811 Dryer and make the switch.
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who have you been talking to at brown?
I've talked to Mike over the phone and Matt in person. Matt come out one day a couple of weeks ago to see what he could do for me. Of course the problem didn't show itself while he was here.

He had me raise the heat panels a couple of inches and completely turn off the forced air. I am a little disappointed that he didn't check any of the electrical components, but then again Brown is convinced this is user error.
weird, they are always good to me. Wish I was closer I would check it out for you
I agree, Mike, Matt, and Andrew have all been very nice to work with. I also understand their point of view on the subject.

This is just one of those things in life that I will have to live with and adjust my workflow to accomodate this dryer. I will do my best to figure this out.

I have had a couple of other problems with the dryer, such as a bad temp controller and a noisy belt drive motor. Mike sent out new parts for each with no hassle whatsoever. Great people to work with, but for me the jury is still out the quality of the equipment.

As for my temp problems, I just ran a job of WHITE ink on BLACK SPIDER tie tye this morning. The first two sets of 6 shirts came out at 340-350. The next 2 sets came out at 360-370.

I can understand and live with a +/- of 7F to 10F degrees but the 20 to 30 that I get is costing me time and money.
Yesterday went without a hitch. I made a few adjustments, lowering the heat panels, lowering the front panel temp, and turned on the forced air.

I was able to print black shirts front and back as well as royal shirts front, back, and sleeve. Normal temp variations that were expected and controlled by adjusting belt speed. I had the doors open and the fans on full speed all day.

Matt from Brown Mfg. called me this morning and has given me an offer to make things right. The offer is more than I requested and more than fair in my opinion. :)
Hello Mark sorry to hear what's happening to your dryer but i been reading all the information you posted and in my opinion it could be a malfunction with the relays, see the relays are the one who tell the heating elements when to turn on and off sometimes the relay crack open in the inside exposing voltages and giving the wrong information to the elements I am pretty sure that's the problem with the dryer because when you start the dryer the temperature holds for a few minutes and then drops 20 to 30 F which only means that is an element completely off and of course your ambient temperature wont detect it because the thermometer is located in the middle of the dryer unless the failure is in the middle elements I hope you can check that before you spend more money in it.
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Thanks for the info XAIME.

I talked to Mike yesterday and we put togehter a plan of attack to get me back up and running properly.

If I knew how to check the relays myself I would. So far I've been lucky in not getting fried while checking the main voltage and amps.:D
Today I have problems again. The temp settings I have used for the last 2 days are no longer working for me. Dryer has been running for 2 hours and the out temp of the shirts is about 315F, down from the 340-350 from a couple of days ago.

I have recorded volts and amp coming in to the dryer. I am not an electrical genius so I have no idea if these are normal or not:

The reading below are the same readings I was getting when the dryer was working fine the other day, but today I'm getting less heat.

3 phase setup
volts ~238 amps ~42
relay volts ~150

volts ~238 amps ~42
relay volts ~150

volts ~238 amps ~28
relay volts ~125

Seems to me the white has issues...or is that normal?
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Wow Mark those reading are a Little weird to me but lets not focus on that ok.
First tell me what kind of heating elements do you have, what brand the dryer is and if its possible to find the owner manual.

1. check for burned wires attach to the heating elements, loose connections, broken heating elements and any indication of wires out of place.

If any of the wires look burned change it sometimes the wires when overheat they cracked inside making a slightly contact with the elements letting them heat up for a few minutes and then stop working properly.( always use high temperature cable to replace a broken connection around the heat elements usually call insulated cable). To replace any cable always have your dryer disconnected from the main switch.

2.If everything look ok, get your tester and proceed to test every single one of the element while the dryer is on and check for any variation on the volts going to the elements, your reading should be between 235V and 240V make sure your tester is in ~.
2.1 your reading variate going low and high, one of your relay is not working properly, or a cable going of the relay is loose and is making a false contact.
2.2 the Reading of 240V is correct but the heating element seems to be colder than the other ones, it needs to be replace, it could be broken and is not working properly.

3.everything appear to be working correctly inside the dryer, you have to check for the main electric connection. If the cable is extremely hot it could be a loose connection going in the dryer. where the fuses go. Check all the fuses and make sure they are all in working condition if you have doubts about any of them replace them. make sure the fuses box were they are is not loose at all, from any connector or screw. And always make sure your dryer is disconnect from the main electricity to do all that.
3.1 Make sure the cable (240V) is not overheating
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Thanks again XAIME. :)

The dryer is a Brown UltraSierra 4811. I have checked all connections and wires as best I can. There is nothing else I can do now. The dryer ran without a hitch today and I'm hoping tomorrow goes good as well.

I am so far behind because of the dryer issues that I print everything I can on the GOOD days. I am just hoping my shirts are being cured properly. At this point I just cross my fingers and hope for the best. I have about 100 pieces of customer supplied Nike 100% poly teamwear that needs to get done this week. I pray the dryer gives me a few good days to get through this job without over/under curing.

This is NOT the way to run a successful screen printing business.:(

I am waiting to hear back from Brown. Mike is conversing with his team to see what we should try next. We are thinking of converting back to single phase to see if it makes any difference.
Today was another good day with the dryer. It appears to be holding steady temps. I say appears because I have no idea what temp my shirts are curing at.

Between the 2 laser temp guns and the paper test strips, I get 3 completely different results.:confused: I realize the guns and strips will react differently, but which do I trust?

Has anyone ever used the Atkins Donut Probe? I think this is the only way I'm ever going to get a true and accurate reading.
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