Jeff Thompson Posted July 11, 2023 Report Share Posted July 11, 2023 Hi everyone, I've learned a ton from other posts on this forum but am kind of stuck and could use some help! I recently bought an old Paragon A-66B (and the AA-6B top ring), which appeared to be in pretty good shape for the price. This was meant to upgrade from my tiny Skutt Firebox kiln, which has been great. But after poking around inside and researching online, I realized that the Paragon kiln uses a funky four-wire, 120/220 volt system. It would require an unusual circuit in my studio and is making it harder to figure out how to move to a digital controller. The Paragon kiln currently has three 3-position switches and a kiln sitter, but the wiring is real crusty and I've gotten spoiled with digital control. I've looked into digital controllers and have a few in mind, but I'm a bit stuck on how to wire this up. A few questions that I would really appreciate some help on! Can I gut the existing wiring, have no switches, and connect the new controller directly to the elements? (I realize this would remove the kiln sitter as a safety.) Paragon suggested this would be possible but wouldn't give me any specific suggestions. I'm not in a shared studio so I'm not concerned that the kiln will be powered on when the controller is on. If I did go this route, would the elements be wired in series or parallel? I have a 50-amp circuit ready to go, but the kiln requires about 30 amps – Paragon suggested this would be dangerous since the kiln would have to go very wrong before the breaker is flipped. Is there a way to insert a 30 amp fuse in between the controller and the kiln? I'd really love to stick with a 50 amp system so I can easily move to a larger kiln in the future, and use the circuit for a welder etc as needed I'd like to avoid the drop-in kiln sitter replacement controllers, since it's a lot of money and only works with one kiln, and it seems it will be difficult to use it with the current four-wire setup. I've done lots of house wiring and lower voltage electronics, so I feel pretty good about doing the work safely, I just need some help figuring out the way to go here. Thanks everyone, this community is so great! Quote Link to comment Share on other sites More sharing options...
Dick White Posted July 11, 2023 Report Share Posted July 11, 2023 Two thoughts" I am assuming you would be constructing your own digital controller from a raw Bartlett controller and all the associated parts. As you have discovered, there are no pre-built wall-hung controllers that support a 4-wire power supply. Yes, you could remove the kiln sitter and control boxes with the switches and directly connect the controller's relay outputs to the kiln elements. That would require building new or adapting the old control boxes to appropriately contain the connections, and lengths of appropriate cable from the digital controller to the kiln. I have done this with several manual kiln conversions, though not with a 4-wire Paragon, but being familiar with the Paragon wiring diagrams, in theory it should be possible. You will need to be facile with wiring diagrams, basic metal working, some electrical skills, and understanding of element resistance/amps/etc. It's not a job for the faint of heart. As for your 50 amp circuit, the ampacity of the circuit should be at least 125% of the total rated ampacity of the kiln (including the extension ring if you make that a permanent part of the kiln), but not more than 150%. You didn't say what the rating plate(s) on the kiln show (i.e., is the 30 amps you mentioned the actual kiln amperage (including the extension) or just what somebody told you was what the kiln needed), but you can do the calculations yourself. If the ampacity of the circuit needs to be downrated for this kiln, you can achieve that simply by putting an appropriate lower rated breaker in the panel. There is nothing wrong with having heavier 50 amp wire servicing a 30 amp breaker. The heavier wire will be fine. Just don't do it the other way with a heavier breaker servicing lighter wire. Be aware that the limit of this 50 amp circuit is a 40 amp kiln. The larger plug-in kilns on the market are all 48 amps and require a 60 amp circuit. Bill Kielb and Jeff Thompson 2 Quote Link to comment Share on other sites More sharing options...
neilestrick Posted July 12, 2023 Report Share Posted July 12, 2023 Post a picture of the serial plate on the kiln and expansion ring. Also, measure the resistance of each element. How many elements total? According to the info I'm seeing on Paragon's site, there are two elements in the main kiln and two in the expansion ring? You can probably rewire the elements in series and run them off a 3 wire system, but let's see the numbers to make sure. Jeff Thompson 1 Quote Link to comment Share on other sites More sharing options...
Jeff Thompson Posted July 12, 2023 Author Report Share Posted July 12, 2023 (edited) Thanks Dick and Neil, very helpful! Controller: I knew I was going to forget something important! My hope is to use a wall mounted controller. It seems like the best investment since I can use it with future kilns too. (Which is also why I was looking at 50 amp models even though my kiln doesn't need that much power.) I spent a bunch of time researching building my own controller, but even though the basics are pretty straightforward I got worried about safety, plus with good quality relays it's not that much cheaper, as far as I could tell. Amperage: That's a great suggestion! I never thought to swap out the breaker, but that's a cheap and easy way to go, and makes me feel a lot better. The plates on the kiln say 21.6 amps total, so it seems like a 40 amp breaker would be ideal? Do you think this would cause any potential damage to the controller if it's rated for 50 amps? Or will it just trip the breaker and turn everything off? Serial plate/elements: Photo attached. There are three elements, two in the bottom and one in the expansion ring. The bottom ones are supposed to be 7.5 ohms each, the top 35 ohms (I think, I have it written down at home). Edited July 12, 2023 by Jeff Thompson Quote Link to comment Share on other sites More sharing options...
neilestrick Posted July 12, 2023 Report Share Posted July 12, 2023 Running lower amperage through a 50 amp controller relay won't harm it in any way. In fact it'll last longer because of the lower amperage. By the math it looks like you can wire the two main elements in series which puts the total resistance at 15 ohms, and run them on 240 volts (240/15=16 amps). If the single expansion ring element is 35-ish ohms then it runs on 240 volts also. Disconnect the switches and wire the elements directly to the Kiln Sitter terminals. Then plug the kiln into a wall mount controller and you're up and running. You can build your own wall mount with a Genesis Mini controller for about $650 and save yourself a bunch of money. Jeff Thompson 1 Quote Link to comment Share on other sites More sharing options...
Jeff Thompson Posted July 17, 2023 Author Report Share Posted July 17, 2023 Thanks again Neil! Sorry got caught up with other stuff but I really appreciate the help. I have a line on a Skutt KM-1 for super cheap and was hoping to go with that. Attached is how I think this is supposed to be wired (ignoring the details of the kiln sitter). Does this look correct? Quote Link to comment Share on other sites More sharing options...
neilestrick Posted July 17, 2023 Report Share Posted July 17, 2023 2 hours ago, Jeff Thompson said: Thanks again Neil! Sorry got caught up with other stuff but I really appreciate the help. I have a line on a Skutt KM-1 for super cheap and was hoping to go with that. Attached is how I think this is supposed to be wired (ignoring the details of the kiln sitter). Does this look correct? No. The top section will connect to both hots, the big section will have the two elements in series. Jeff Thompson 1 Quote Link to comment Share on other sites More sharing options...
Jeff Thompson Posted July 17, 2023 Author Report Share Posted July 17, 2023 Thanks Neil, you're amazing! Quote Link to comment Share on other sites More sharing options...
Jeff Thompson Posted September 14, 2023 Author Report Share Posted September 14, 2023 A huge thanks again to Neil, Dick, and everyone in my other post who helped me get this working! The kiln is currently test firing as we speak and so far the Skutt wall-mounted controller is working great. This was a great project even though it took waaay more work and time (and $$$) than I expected, but the tradeoff has been I really know this kiln inside and out. If something goes wrong in the future, I feel like I know how to fix any part. Definitely not a good project for folks who don't know how to work safely with high temp and voltage, but if you've wired some outlets and messed with wiring other tools it's not too bad. Pictures of the results attached. I couldn't help myself and laser-engraved a custom tag for the aptly-named Frankenkiln! Quote Link to comment Share on other sites More sharing options...
neilestrick Posted September 14, 2023 Report Share Posted September 14, 2023 It looks great! Quote Link to comment Share on other sites More sharing options...
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