DK 1020-2

[Retxy]

Hi Everyone,

I have a very old Duncan DK 1020-2 that i have ben trying to contact Paragon for help with, but cant seem to get complete answers for.

It turns on but when i turn the knob for the upper switches, sparks fly from the top of the box. 

I am looking at the digram on the paragon website(attached) but its a copy and the lettering is hard to read and searches on the website for part numbers dont yield anything. 

My very best guess is that the old rusty screws holding the bars (see pic) need to be replaced. Will stainless machine screws be sufficient for that? And the bars look ok, but can someone tell me what they are called so I can send an inquiry to another company like Euclids, who have been very responsive and may just be able to help?

And if ayonehas an opinion on if the wires within need to be changed, please feel free to share. I think they work ok but didnt test the elements due to sparking. I am assuming i can strip back the sheaths a bit to ascertain guage and order similar sized ones... and also what the heck is a u terminal? 

Sorry for the 10million questions and thanks again for all of the help!!

retxy

W-DA-1020-2-4-Control-Panel.pdf

[PeterH]

To me this version of the diagram looks slightly less unreadable

 

[PeterH]

3 hours ago, Retxy said:

searches on the website for part numbers dont yield anything. 

Might be of marginal interest re the availability of the 4300 & 4600 timers.

...Which includes
Yeah, I consulted with Paragon before posting here and their kiln tech told me the same thing... Well she said they do have the timers for the ones with two timers (like mine), but apparently some of these Duncan kilns had a single, combined timer that they don't have available anymore. Just saying this to spread the knowledge...

Edited August 27 by PeterH

[neilestrick]

Lots of corrosion in there. Are the sparks coming from the switch or from a wiring connection? The bars between the elements are called bus bars, but they are used on very few kilns- mostly just Duncan and the Skutt PK models. They're just stainless steel plates. I would just sand them down to remove any surface crud and they'll be good to go. You can replace any of the nuts and bolts with stainless steel parts from the hardware store. I would rewire it as long as you're at it since there is a lot of discoloration in the wire casing which indicates overheating. Use #12 SRML wire. All terminals where the wires connect to the elements must be high temp terminals. Not a bad idea to use them for the ends that connect to the switches, too. If the switches are bad, the best option is to replace them with infinite switches. I like Robert Shaw switches, any 240V 15 amp switch kit will work. Your box does not appear to have the timer switches at the bottom, so that simplifies things.

[Bill Kielb]

I agree wit Neil’s assessment for the most part. The buss bars can be cleaned and screws replaced. Copper is best so if they are copper - no worries they conduct heat much better. Most kiln buss bars last forever with a little maintenance. The electrical connections are very important so clean tight connections are critical. SMRL (small motor lead wire) is ok and cost savings for today’s kilns. SMRL was developed for flexibility and vibration as well as moderately high temp (150c-200c) operation. Your kiln was very likely wired with MG (mica glass wire) -450c so I am in favor of replacing with MG rather than lower rated SMRL New kilns today, better design ventilation, SMRL is a money saver though. If the Old MG is in good condition, cutting back to clean wire and installing new high temp connector would be reasonable IMO. 

Sparks - gotta locate these, just looking at your pictures (hard to tell from the pic), the missing wire I would guess is involved and the top element connection looks in need of maintenance. Circled pics below.

Lastly this is a semi automatic kiln with the mysterious timer relays. The timers are costly or not available and tend to add confusion to firing. I think Neil is in favor and my preference would be to remove most of that and replace with 2 infinite switches, no relays at all would be my goal. The existing relay is 240 v coil and uses the normally closed contacts so super confusing unless you are into control  methodology.

Add - skip the broken wire idea, appears to  be element tail

 

Edited August 28 by Bill Kielb

[Retxy]

@neilestrickIm not quite sure exactly where the sparks are coming from only that its at the top right hand cornern of the box, well above whre the switches are if that helps. It happened when turning on the top switch to on. I panicked and shut it off pretty quick but it wasnt continuous sparking and it didnt trip anything off.  Whatever if anything that means. 

I wrote euclids and they suggested that 12g SEW wires can replace bus bars and that i can then use the more typical brass connectors that my other kilns use... do you think thats a good idea? Ive been really really impressed with Euclids and they have been way, way more helpful than paragon. 

Thanks so much for the 15V switch kit information! Is this something i can check viability of via voltmeter? Or is the simple act of it is powering elements proof switch isn't bad? Awfully dumb question, I know, but electrician i am not. Clearly ahahah!

@PeterH thank you so much for the lovely links you provided!! youre right, that wiring diagram is less offensive than the one i got from the paragon website!! Thank you!

 

@Bill Kielb

Thank you for the advice!! Is smrl the same as SEW wire? Do you think 12G SEW replacement suggested by Euclids is safe given the mica wire? Also, there are akready two infinite switches on this model... at least the manual says they are infinite. Then knobs are missing but the info i got on the switches is that they are infinite.  Did i mess up somewhere and this isnt true?

In lieu of fenagling all these old components is there a solution that would let me replace the guts of this control box (or just replace the whole box) with a better way to power the innards? Doubt i can afford, but a digital option would be a nice pipe dream. 

Thanks again to all of you for your help!!

[Bill Kielb]

10 hours ago, Retxy said:

Thank you for the advice!! Is smrl the same as SEW wire? Do you think 12G SEW replacement suggested by Euclids is safe given the mica wire? Also, there are akready two infinite switches on this model... at least the manual says they are infinite. Then knobs are missing but the info i got on the switches is that they are infinite.  Did i mess up somewhere and this isnt true?

My opinion / experience
12 Gauge SEW wire is very similar to SMRL rated about 200C and braided over silicone. SEW more of a Canadian specification I believe. Neither SMRL or SEW meet or exceed the MG wire that your kiln likely was built with (-450C) so in that sense the MG is superior. All will likely work fine though, I am just an old engineer. (Very old).

With respect to the buss bars, they look corroded, so I would wire brush (Dress) the bars and ends to remove all the corrosion and reinstall with new bolt hardware (low cost, mainly labor). The bus bars are better than any wire and crimp or clamp connection IMO (for several reasons) and if replacing with wires these connections would need to be thoroughly cleaned anyway and new bolt and nut hardware for ring terminal type wire termination (Presently on your kiln element leads) when replacing with wire. One could butt splice the wire directly to the element as well but this introduces an additional splice to the connection and is not easily removable during future element change out.

Since the element tales will be well beyond 400c at points in the firing, the mg in my mind is superior. The buss bars cool themselves because of the metal surface and are rated well beyond 400C. To me clean buss bars = best, MG wire good, lesser rated wire would be my third choice. All should work though.

Looking at your picture, this kiln appears to have been rewired removing the old time delay relays and installing two infinite switches which is good news IMO.

For me I would:

• Clean all buss bars and connections and reinstall with new nuts and bolts
• Check all remaining connections, clean and install new crimp or nut and bolt hardware.
• Check the infinite switch operation, maybe anticipate installing two new because they are fairly economical
• Measure the element resistance to see if they are worn. This would be the most costly and I am going to guess likely needed and you ought to check first from a budget perspective.

For future digital control you would need a controller, power transformer, relays to replace the infinite switches,  thermocouple(s) misc wire and assorted mounting hardware. If you are handy or know someone (reasonably skilled) that can help, I would guess $250.00 - $500.00 using an older Bartlett V6cf control and fitting it into the control box. @neilestrick probably has a preference here based on ease of retrofit install and available space in the control box. I have in the past drawn up a solution for friends  that uses a separate control box for the controller, relays, transformer, etc… that gets bolted right to the front of this panel. It is economical but definitely takes a bit of effort and wiring skills.

Late add - this is the diagram for the DK kiln it can be found in the appendix of their service manual and can be downloaded https://corp.paragonweb.com/wp-content/uploads/LX_809_Duncan_Kiln_Service_Manual-1.pdf

Its a simple kiln - no electronic timers

Edited Thursday at 02:42 PM by Bill Kielb

[neilestrick]

I like the buss bars. They last a lot longer than wires, however the bolts that came with these kilns tends to corrode badly. If you can get the buss bars cleaned up and replace all the nuts and bolts with stainless steel it would work great. If not, then jumper wires will be fine.

I wouldn't even try to mount a digital system into the existing control box. I'd only use an external box, either wall mounted or mounted to the existing box. You could build it yourself for $600-ish, but if you're not handy with wiring then I would recommend buying a system, which will cost more like $1000+ with a touch screen controller.

[neilestrick]

Skutt is using Radix Sil-A-Blend 250C for their wires, which are a silicone jacket, no fiberglass. L&L has also switched over to a silicone jacket for some of their wiring, but are still using SRML as well. I don't know what brand their silicone wire is. I'll have to check that out next time I set up a kiln. I have not been able to find Sil-A-Blend 200C or 250C wire sold by the foot, though. It's only available in larger rolls, which would be enough for several lifetimes for a typical kiln owner. SRML (200C), TGGT (250C), and MG (450C) are all available by the foot from a number of online vendors. Most have very similar prices. For 12awg:

• SRML $0.73/ft
• TGGT $1/ft
• MG $1.88/ft for the regular stuff
• MG $2.40/ft for the good flexible stuff

[Retxy]

@Bill Kielb @neilestrick

 

Thank you both so much for all of your help. In light of all this information, my preference would be to keep the buss bars and i found some mg wire on the 'zon: https://www.amazon.com/Bryne-Temperature-Insulation-Fiberglass-environments/dp/B07W3DHBT3/ref=asc_df_B07W3DHBT3/?tag=hyprod-20&linkCode=df0&hvadid=693335572470&hvpos=&hvnetw=g&hvrand=15503763948076310371&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9011346&hvtargid=pla-816415257518&psc=1&mcid=dc7d7aeac0ef3e40ba598ce8a4db3adc

Im not handy but my father is also a very old engineer whom i love very much and therefore tax very often. I might be able to run some of those ideas by him to see how willing he is to suffer. But my feeling is that im going to have to find a kiln tech in GA to do anything beyond a simple rewiring/element replacement (long overdue) and metal cleaning, all of which i feel i can reasonably minimally mess up.

I love the idea of an external box that i could interface with different kilns in the future, so I will be looking into that. All I've seen so far is the orton line, but i know there are others just need to read up. For now, will focus on the suggestions you have made and pray this works.

Thank you again so so much for all of the help!!!

[Bill Kielb]

2 hours ago, Retxy said:

i found some mg wire on th

@Retxy Just a notice

I have had trouble with some of these, I am not a fan of Amazon for wire - any type insulation.  Regular professional wire suppliers are generally equal price or even more economical with a dependable specification. Here is one https://prowireandcable.com/12-awg-1-conductor-65-strands-mg-mica-glass/

The Amazon link has a few negative reviews that I have seen before and are worrisome. This wire has been around for 50 plus years and has a very straightforward minimum specification. Hard to tell the full assured specs from Amazon. I always go with something from a local reputable wire supplier - maybe just me though.

The element leads are likely 14 Gauge (prox. no more than 15 amps per element lead) the existing, where long enough, can simply be cut back an inch or so to clean wire and a new crimp installed. Please use real crimpers and crimp all terminals tight though.

If you are unsure of the gauge, 12 gauge element leads are more than capable for this kiln and you could replace just the wires that aren’t long enough for the cut back and new terminal fix. Usually most can be trimmed and recrimped with 1 or 2 leads that are just too short. Often I’ll order 10-20’ and it’s enough for several kilns. In this way, it’s mostly a terminal replacement, cleanup, and new hardware project.

wire brush, fine sandpaper very likely gets the buss bars very clean. Where they physically connect is important, the rest not so much. A wire wheel on a drill can work wonders for hard to reach surfaces.

Edited Sunday at 12:19 AM by Bill Kielb

[Retxy]

@Bill Kielb 

Thank you for the insight on where to order the wire!! Amazon is such a thoughtless reflex these days that I didn't even think there might be a better option out there.

Both paragon and euclids suggested the wire be 12 awg but we were talking about SEW at the time, but i feel better with a wire hat can handle hotter temps. Hopefully its as you say and I may be able to just cut back on whats already there, but honestly given the corrosion and the already sparking events, I think renewing everything is the safer way to go. I am afraid I might burn down the neighborhood otherwise. 

As far as the terminals go, u terminals are listed in the documentation ... these crimp at the wire end, right? There are no other crimps needed?

Also would a rust removal product be ok, or manual removal only?

I cant thank you enough. Sorry some of these questions are so basic, but my neighbors thank you for saving their homes from my accidental incindiaries. 

[Bill Kielb]

14 hours ago, Retxy said:

As far as the terminals go, u terminals are listed in the documentation ... these crimp at the wire end, right? There are no other crimps needed?

I would use high temperature (non insulated) ring terminals rather than U shaped given a choice, they are less likely to spread when tightening. Some crimps at the end of wires is a yes. Either are fine though. Wire generally does not wear out so cutting back any corrosion to bright clean wire and  adding a new well made crimp is pretty standard type repair. If the wire has overheated and has become brittle throughout its length then the wire has worn out. Replacing is certainly better especially with new 12 Gauge so if the budget permits I believe that will be superior. Wire insulation can dry out and begin to degrade by cracking / delaminating etc…  MG wire generally does not  do this to the level of say an old lamp cord but thorough inspection before reuse necessary and full replacement is definitely fantastic.

 

14 hours ago, Retxy said:

Also would a rust removal product be ok, or manual removal only?

I like removal products for the parts I will repaint. The corrosion on the electrical stuff should be removed by wire brush and or fine sanding to bright metal. No need to grind these down, just make them bright clear metal where they contact each other. Rust remover, not really for electrical corrosion.

Renewing all IMO makes this kiln like new.

Edited yesterday at 05:24 PM by Bill Kielb